block: remove struct request buffer member

This was used in the olden days, back when onions were proper
yellow. Basically it mapped to the current buffer to be
transferred. With highmem being added more than a decade ago,
most drivers map pages out of a bio, and rq->buffer isn't
pointing at anything valid.

Convert old style drivers to just use bio_data().

For the discard payload use case, just reference the page
in the bio.

Signed-off-by: Jens Axboe <axboe@fb.com>

23 files changed, 55 insertions, 75 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 1fe9ff6e6802..ae6227fd07aa 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -146,8 +146,8 @@ void blk_dump_rq_flags(struct request *rq, char *msg)
         printk(KERN_INFO "  sector %llu, nr/cnr %u/%u\n",
                (unsigned long long)blk_rq_pos(rq),
                blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
-        printk(KERN_INFO "  bio %p, biotail %p, buffer %p, len %u\n",
-               rq->bio, rq->biotail, rq->buffer, blk_rq_bytes(rq));
+        printk(KERN_INFO "  bio %p, biotail %p, len %u\n",
+               rq->bio, rq->biotail, blk_rq_bytes(rq));
 
         if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
                 printk(KERN_INFO "  cdb: ");
@@ -1360,7 +1360,6 @@ void blk_add_request_payload(struct request *rq, struct page *page,
 
         rq->__data_len = rq->resid_len = len;
         rq->nr_phys_segments = 1;
-        rq->buffer = bio_data(bio);
 }
 EXPORT_SYMBOL_GPL(blk_add_request_payload);
 
@@ -1402,12 +1401,6 @@ bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
         bio->bi_next = req->bio;
         req->bio = bio;
 
-        /*
-         * may not be valid. if the low level driver said
-         * it didn't need a bounce buffer then it better
-         * not touch req->buffer either...
-         */
-        req->buffer = bio_data(bio);
         req->__sector = bio->bi_iter.bi_sector;
         req->__data_len += bio->bi_iter.bi_size;
         req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
@@ -2434,7 +2427,6 @@ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
         }
 
         req->__data_len -= total_bytes;
-        req->buffer = bio_data(req->bio);
 
         /* update sector only for requests with clear definition of sector */
         if (req->cmd_type == REQ_TYPE_FS)
@@ -2752,10 +2744,9 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
         /* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw */
         rq->cmd_flags |= bio->bi_rw & REQ_WRITE;
 
-        if (bio_has_data(bio)) {
+        if (bio_has_data(bio))
                 rq->nr_phys_segments = bio_phys_segments(q, bio);
-                rq->buffer = bio_data(bio);
-        }
+
         rq->__data_len = bio->bi_iter.bi_size;
         rq->bio = rq->biotail = bio;
 
@@ -2831,7 +2822,7 @@ EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
 
 /*
  * Copy attributes of the original request to the clone request.
- * The actual data parts (e.g. ->cmd, ->buffer, ->sense) are not copied.
+ * The actual data parts (e.g. ->cmd, ->sense) are not copied.
  */
 static void __blk_rq_prep_clone(struct request *dst, struct request *src)
 {
@@ -2857,7 +2848,7 @@ static void __blk_rq_prep_clone(struct request *dst, struct request *src)
  *
  * Description:
  *     Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
- *     The actual data parts of @rq_src (e.g. ->cmd, ->buffer, ->sense)
+ *     The actual data parts of @rq_src (e.g. ->cmd, ->sense)
  *     are not copied, and copying such parts is the caller's responsibility.
  *     Also, pages which the original bios are pointing to are not copied
  *     and the cloned bios just point same pages.
diff --git a/block/blk-map.c b/block/blk-map.c
index f7b22bc21518..f890d4345b0c 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -155,7 +155,6 @@ int blk_rq_map_user(struct request_queue *q, struct request *rq,
         if (!bio_flagged(bio, BIO_USER_MAPPED))
                 rq->cmd_flags |= REQ_COPY_USER;
 
-        rq->buffer = NULL;
         return 0;
 unmap_rq:
         blk_rq_unmap_user(bio);
@@ -238,7 +237,6 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
         blk_queue_bounce(q, &bio);
         bio_get(bio);
         blk_rq_bio_prep(q, rq, bio);
-        rq->buffer = NULL;
         return 0;
 }
 EXPORT_SYMBOL(blk_rq_map_user_iov);
@@ -325,7 +323,6 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
         }
 
         blk_queue_bounce(q, &rq->bio);
-        rq->buffer = NULL;
         return 0;
 }
 EXPORT_SYMBOL(blk_rq_map_kern);
diff --git a/drivers/block/amiflop.c b/drivers/block/amiflop.c
index 748dea4f34dc..758da2287d9a 100644
--- a/drivers/block/amiflop.c
+++ b/drivers/block/amiflop.c
@@ -1406,7 +1406,7 @@ next_segment:
 
                 track = block / (floppy->dtype->sects * floppy->type->sect_mult);
                 sector = block % (floppy->dtype->sects * floppy->type->sect_mult);
-                data = rq->buffer + 512 * cnt;
+                data = bio_data(rq->bio) + 512 * cnt;
 #ifdef DEBUG
                 printk("access to track %d, sector %d, with buffer at "
                        "0x%08lx\n", track, sector, data);
diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c
index 96b629e1f0c9..7e8a55f8917c 100644
--- a/drivers/block/ataflop.c
+++ b/drivers/block/ataflop.c
@@ -1484,7 +1484,7 @@ repeat:
         ReqCnt = 0;
         ReqCmd = rq_data_dir(fd_request);
         ReqBlock = blk_rq_pos(fd_request);
-        ReqBuffer = fd_request->buffer;
+        ReqBuffer = bio_data(fd_request->bio);
         setup_req_params( drive );
         do_fd_action( drive );
 
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 8f5565bf34cd..5f69c910c3ac 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -2351,7 +2351,7 @@ static void rw_interrupt(void)
         }
 
         if (CT(COMMAND) != FD_READ ||
-            raw_cmd->kernel_data == current_req->buffer) {
+            raw_cmd->kernel_data == bio_data(current_req->bio)) {
                 /* transfer directly from buffer */
                 cont->done(1);
         } else if (CT(COMMAND) == FD_READ) {
@@ -2640,7 +2640,7 @@ static int make_raw_rw_request(void)
                 raw_cmd->flags &= ~FD_RAW_WRITE;
                 raw_cmd->flags |= FD_RAW_READ;
                 COMMAND = FM_MODE(_floppy, FD_READ);
-        } else if ((unsigned long)current_req->buffer < MAX_DMA_ADDRESS) {
+        } else if ((unsigned long)bio_data(current_req->bio) < MAX_DMA_ADDRESS) {
                 unsigned long dma_limit;
                 int direct, indirect;
 
@@ -2654,13 +2654,13 @@ static int make_raw_rw_request(void)
                  */
                 max_size = buffer_chain_size();
                 dma_limit = (MAX_DMA_ADDRESS -
-                             ((unsigned long)current_req->buffer)) >> 9;
+                             ((unsigned long)bio_data(current_req->bio))) >> 9;
                 if ((unsigned long)max_size > dma_limit)
                         max_size = dma_limit;
                 /* 64 kb boundaries */
-                if (CROSS_64KB(current_req->buffer, max_size << 9))
+                if (CROSS_64KB(bio_data(current_req->bio), max_size << 9))
                         max_size = (K_64 -
-                                    ((unsigned long)current_req->buffer) %
+                                    ((unsigned long)bio_data(current_req->bio)) %
                                     K_64) >> 9;
                 direct = transfer_size(ssize, max_sector, max_size) - fsector_t;
                 /*
@@ -2677,7 +2677,7 @@ static int make_raw_rw_request(void)
                        (DP->read_track & (1 << DRS->probed_format)))))) {
                         max_size = blk_rq_sectors(current_req);
                 } else {
-                        raw_cmd->kernel_data = current_req->buffer;
+                        raw_cmd->kernel_data = bio_data(current_req->bio);
                         raw_cmd->length = current_count_sectors << 9;
                         if (raw_cmd->length == 0) {
                                 DPRINT("%s: zero dma transfer attempted\n", __func__);
@@ -2731,7 +2731,7 @@ static int make_raw_rw_request(void)
         raw_cmd->length = ((raw_cmd->length - 1) | (ssize - 1)) + 1;
         raw_cmd->length <<= 9;
         if ((raw_cmd->length < current_count_sectors << 9) ||
-            (raw_cmd->kernel_data != current_req->buffer &&
+            (raw_cmd->kernel_data != bio_data(current_req->bio) &&
              CT(COMMAND) == FD_WRITE &&
              (aligned_sector_t + (raw_cmd->length >> 9) > buffer_max ||
               aligned_sector_t < buffer_min)) ||
@@ -2739,7 +2739,7 @@ static int make_raw_rw_request(void)
             raw_cmd->length <= 0 || current_count_sectors <= 0) {
                 DPRINT("fractionary current count b=%lx s=%lx\n",
                        raw_cmd->length, current_count_sectors);
-                if (raw_cmd->kernel_data != current_req->buffer)
+                if (raw_cmd->kernel_data != bio_data(current_req->bio))
                         pr_info("addr=%d, length=%ld\n",
                                 (int)((raw_cmd->kernel_data -
                                        floppy_track_buffer) >> 9),
@@ -2756,7 +2756,7 @@ static int make_raw_rw_request(void)
                 return 0;
         }
 
-        if (raw_cmd->kernel_data != current_req->buffer) {
+        if (raw_cmd->kernel_data != bio_data(current_req->bio)) {
                 if (raw_cmd->kernel_data < floppy_track_buffer ||
                     current_count_sectors < 0 ||
                     raw_cmd->length < 0 ||
diff --git a/drivers/block/hd.c b/drivers/block/hd.c
index bf397bf108b7..8a290c08262f 100644
--- a/drivers/block/hd.c
+++ b/drivers/block/hd.c
@@ -464,11 +464,11 @@ static void read_intr(void)
 
 ok_to_read:
         req = hd_req;
-        insw(HD_DATA, req->buffer, 256);
+        insw(HD_DATA, bio_data(req->bio), 256);
 #ifdef DEBUG
         printk("%s: read: sector %ld, remaining = %u, buffer=%p\n",
                req->rq_disk->disk_name, blk_rq_pos(req) + 1,
-               blk_rq_sectors(req) - 1, req->buffer+512);
+               blk_rq_sectors(req) - 1, bio_data(req->bio)+512);
 #endif
         if (hd_end_request(0, 512)) {
                 SET_HANDLER(&read_intr);
@@ -505,7 +505,7 @@ static void write_intr(void)
 ok_to_write:
         if (hd_end_request(0, 512)) {
                 SET_HANDLER(&write_intr);
-                outsw(HD_DATA, req->buffer, 256);
+                outsw(HD_DATA, bio_data(req->bio), 256);
                 return;
         }
 
@@ -624,7 +624,7 @@ repeat:
         printk("%s: %sing: CHS=%d/%d/%d, sectors=%d, buffer=%p\n",
                 req->rq_disk->disk_name,
                 req_data_dir(req) == READ ? "read" : "writ",
-                cyl, head, sec, nsect, req->buffer);
+                cyl, head, sec, nsect, bio_data(req->bio));
 #endif
         if (req->cmd_type == REQ_TYPE_FS) {
                 switch (rq_data_dir(req)) {
@@ -643,7 +643,7 @@ repeat:
                                 bad_rw_intr();
                                 goto repeat;
                         }
-                        outsw(HD_DATA, req->buffer, 256);
+                        outsw(HD_DATA, bio_data(req->bio), 256);
                         break;
                 default:
                         printk("unknown hd-command\n");
diff --git a/drivers/block/mg_disk.c b/drivers/block/mg_disk.c
index eb59b1241366..e352cac707e8 100644
--- a/drivers/block/mg_disk.c
+++ b/drivers/block/mg_disk.c
@@ -479,7 +479,7 @@ static unsigned int mg_out(struct mg_host *host,
 
 static void mg_read_one(struct mg_host *host, struct request *req)
 {
-        u16 *buff = (u16 *)req->buffer;
+        u16 *buff = (u16 *)bio_data(req->bio);
         u32 i;
 
         for (i = 0; i < MG_SECTOR_SIZE >> 1; i++)
@@ -496,7 +496,7 @@ static void mg_read(struct request *req)
                 mg_bad_rw_intr(host);
 
         MG_DBG("requested %d sects (from %ld), buffer=0x%p\n",
-               blk_rq_sectors(req), blk_rq_pos(req), req->buffer);
+               blk_rq_sectors(req), blk_rq_pos(req), bio_data(req->bio));
 
         do {
                 if (mg_wait(host, ATA_DRQ,
@@ -514,7 +514,7 @@ static void mg_read(struct request *req)
 
 static void mg_write_one(struct mg_host *host, struct request *req)
 {
-        u16 *buff = (u16 *)req->buffer;
+        u16 *buff = (u16 *)bio_data(req->bio);
         u32 i;
 
         for (i = 0; i < MG_SECTOR_SIZE >> 1; i++)
@@ -534,7 +534,7 @@ static void mg_write(struct request *req)
         }
 
         MG_DBG("requested %d sects (from %ld), buffer=0x%p\n",
-               rem, blk_rq_pos(req), req->buffer);
+               rem, blk_rq_pos(req), bio_data(req->bio));
 
         if (mg_wait(host, ATA_DRQ,
                     MG_TMAX_WAIT_WR_DRQ) != MG_ERR_NONE) {
@@ -585,7 +585,7 @@ ok_to_read:
         mg_read_one(host, req);
 
         MG_DBG("sector %ld, remaining=%ld, buffer=0x%p\n",
-               blk_rq_pos(req), blk_rq_sectors(req) - 1, req->buffer);
+               blk_rq_pos(req), blk_rq_sectors(req) - 1, bio_data(req->bio));
 
         /* send read confirm */
         outb(MG_CMD_RD_CONF, (unsigned long)host->dev_base + MG_REG_COMMAND);
@@ -624,7 +624,7 @@ ok_to_write:
                 /* write 1 sector and set handler if remains */
                 mg_write_one(host, req);
                 MG_DBG("sector %ld, remaining=%ld, buffer=0x%p\n",
-                       blk_rq_pos(req), blk_rq_sectors(req), req->buffer);
+                       blk_rq_pos(req), blk_rq_sectors(req), bio_data(req->bio));
                 host->mg_do_intr = mg_write_intr;
                 mod_timer(&host->timer, jiffies + 3 * HZ);
         }
diff --git a/drivers/block/paride/pcd.c b/drivers/block/paride/pcd.c
index e76bdc074dbe..719cb1bc1640 100644
--- a/drivers/block/paride/pcd.c
+++ b/drivers/block/paride/pcd.c
@@ -747,7 +747,7 @@ static void do_pcd_request(struct request_queue * q)
                         pcd_current = cd;
                         pcd_sector = blk_rq_pos(pcd_req);
                         pcd_count = blk_rq_cur_sectors(pcd_req);
-                        pcd_buf = pcd_req->buffer;
+                        pcd_buf = bio_data(pcd_req->bio);
                         pcd_busy = 1;
                         ps_set_intr(do_pcd_read, NULL, 0, nice);
                         return;
diff --git a/drivers/block/paride/pd.c b/drivers/block/paride/pd.c
index 19ad8f0c83ef..fea7e76a00de 100644
--- a/drivers/block/paride/pd.c
+++ b/drivers/block/paride/pd.c
@@ -454,7 +454,7 @@ static enum action do_pd_io_start(void)
                 if (pd_block + pd_count > get_capacity(pd_req->rq_disk))
                         return Fail;
                 pd_run = blk_rq_sectors(pd_req);
-                pd_buf = pd_req->buffer;
+                pd_buf = bio_data(pd_req->bio);
                 pd_retries = 0;
                 if (pd_cmd == READ)
                         return do_pd_read_start();
@@ -485,7 +485,7 @@ static int pd_next_buf(void)
         spin_lock_irqsave(&pd_lock, saved_flags);
         __blk_end_request_cur(pd_req, 0);
         pd_count = blk_rq_cur_sectors(pd_req);
-        pd_buf = pd_req->buffer;
+        pd_buf = bio_data(pd_req->bio);
         spin_unlock_irqrestore(&pd_lock, saved_flags);
         return 0;
 }
diff --git a/drivers/block/paride/pf.c b/drivers/block/paride/pf.c
index f5c86d523ba0..9a15fd3c9349 100644
--- a/drivers/block/paride/pf.c
+++ b/drivers/block/paride/pf.c
@@ -795,7 +795,7 @@ repeat:
         }
 
         pf_cmd = rq_data_dir(pf_req);
-        pf_buf = pf_req->buffer;
+        pf_buf = bio_data(pf_req->bio);
         pf_retries = 0;
 
         pf_busy = 1;
@@ -827,7 +827,7 @@ static int pf_next_buf(void)
                 if (!pf_req)
                         return 1;
                 pf_count = blk_rq_cur_sectors(pf_req);
-                pf_buf = pf_req->buffer;
+                pf_buf = bio_data(pf_req->bio);
         }
         return 0;
 }
diff --git a/drivers/block/skd_main.c b/drivers/block/skd_main.c
index a69dd93d1bd5..36bcedfd930c 100644
--- a/drivers/block/skd_main.c
+++ b/drivers/block/skd_main.c
@@ -563,7 +563,6 @@ skd_prep_discard_cdb(struct skd_scsi_request *scsi_req,
 
         req = skreq->req;
         blk_add_request_payload(req, page, len);
-        req->buffer = buf;
 }
 
 static void skd_request_fn_not_online(struct request_queue *q);
@@ -856,10 +855,10 @@ static void skd_end_request(struct skd_device *skdev,
 
         if ((io_flags & REQ_DISCARD) &&
                 (skreq->discard_page == 1)) {
+                struct bio *bio = req->bio;
                 pr_debug("%s:%s:%d, free the page!",
                          skdev->name, __func__, __LINE__);
-                free_page((unsigned long)req->buffer);
-                req->buffer = NULL;
+                __free_page(bio->bi_io_vec->bv_page);
         }
 
         if (unlikely(error)) {
diff --git a/drivers/block/swim.c b/drivers/block/swim.c
index b02d53a399f3..6b44bbe528b7 100644
--- a/drivers/block/swim.c
+++ b/drivers/block/swim.c
@@ -549,7 +549,7 @@ static void redo_fd_request(struct request_queue *q)
                 case READ:
                         err = floppy_read_sectors(fs, blk_rq_pos(req),
                                                   blk_rq_cur_sectors(req),
-                                                  req->buffer);
+                                                  bio_data(req->bio));
                         break;
                 }
         done:
diff --git a/drivers/block/swim3.c b/drivers/block/swim3.c
index c74f7b56e7c4..523ee8fd4c15 100644
--- a/drivers/block/swim3.c
+++ b/drivers/block/swim3.c
@@ -342,7 +342,7 @@ static void start_request(struct floppy_state *fs)
                 swim3_dbg("do_fd_req: dev=%s cmd=%d sec=%ld nr_sec=%u buf=%p\n",
                           req->rq_disk->disk_name, req->cmd,
                           (long)blk_rq_pos(req), blk_rq_sectors(req),
-                          req->buffer);
+                          bio_data(req->bio));
                 swim3_dbg("           errors=%d current_nr_sectors=%u\n",
                           req->errors, blk_rq_cur_sectors(req));
 #endif
@@ -479,11 +479,11 @@ static inline void setup_transfer(struct floppy_state *fs)
                 /* Set up 3 dma commands: write preamble, data, postamble */
                 init_dma(cp, OUTPUT_MORE, write_preamble, sizeof(write_preamble));
                 ++cp;
-                init_dma(cp, OUTPUT_MORE, req->buffer, 512);
+                init_dma(cp, OUTPUT_MORE, bio_data(req->bio), 512);
                 ++cp;
                 init_dma(cp, OUTPUT_LAST, write_postamble, sizeof(write_postamble));
         } else {
-                init_dma(cp, INPUT_LAST, req->buffer, n * 512);
+                init_dma(cp, INPUT_LAST, bio_data(req->bio), n * 512);
         }
         ++cp;
         out_le16(&cp->command, DBDMA_STOP);
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index efe1b4761735..283a30e88287 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -612,10 +612,10 @@ static void do_blkif_request(struct request_queue *rq)
                 }
 
                 pr_debug("do_blk_req %p: cmd %p, sec %lx, "
-                         "(%u/%u) buffer:%p [%s]\n",
+                         "(%u/%u) [%s]\n",
                          req, req->cmd, (unsigned long)blk_rq_pos(req),
                          blk_rq_cur_sectors(req), blk_rq_sectors(req),
-                         req->buffer, rq_data_dir(req) ? "write" : "read");
+                         rq_data_dir(req) ? "write" : "read");
 
                 if (blkif_queue_request(req)) {
                         blk_requeue_request(rq, req);
diff --git a/drivers/block/xsysace.c b/drivers/block/xsysace.c
index 1393b8871a28..ab3ea62e5dfc 100644
--- a/drivers/block/xsysace.c
+++ b/drivers/block/xsysace.c
@@ -661,7 +661,7 @@ static void ace_fsm_dostate(struct ace_device *ace)
                         rq_data_dir(req));
 
                 ace->req = req;
-                ace->data_ptr = req->buffer;
+                ace->data_ptr = bio_data(req->bio);
                 ace->data_count = blk_rq_cur_sectors(req) * ACE_BUF_PER_SECTOR;
                 ace_out32(ace, ACE_MPULBA, blk_rq_pos(req) & 0x0FFFFFFF);
 
@@ -733,7 +733,7 @@ static void ace_fsm_dostate(struct ace_device *ace)
                          *      blk_rq_sectors(ace->req),
                          *      blk_rq_cur_sectors(ace->req));
                          */
-                        ace->data_ptr = ace->req->buffer;
+                        ace->data_ptr = bio_data(ace->req->bio);
                         ace->data_count = blk_rq_cur_sectors(ace->req) * 16;
                         ace_fsm_yieldirq(ace);
                         break;
diff --git a/drivers/block/z2ram.c b/drivers/block/z2ram.c
index 27de5046708a..968f9e52effa 100644
--- a/drivers/block/z2ram.c
+++ b/drivers/block/z2ram.c
@@ -87,13 +87,15 @@ static void do_z2_request(struct request_queue *q)
                 while (len) {
                         unsigned long addr = start & Z2RAM_CHUNKMASK;
                         unsigned long size = Z2RAM_CHUNKSIZE - addr;
+                        void *buffer = bio_data(req->bio);
+
                         if (len < size)
                                 size = len;
                         addr += z2ram_map[ start >> Z2RAM_CHUNKSHIFT ];
                         if (rq_data_dir(req) == READ)
-                                memcpy(req->buffer, (char *)addr, size);
+                                memcpy(buffer, (char *)addr, size);
                         else
-                                memcpy((char *)addr, req->buffer, size);
+                                memcpy((char *)addr, buffer, size);
                         start += size;
                         len -= size;
                 }
diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index 16f69be820c7..ee880382e3bc 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -188,10 +188,9 @@ static ide_startstop_t ide_do_rw_disk(ide_drive_t *drive, struct request *rq,
 
         ledtrig_ide_activity();
 
-        pr_debug("%s: %sing: block=%llu, sectors=%u, buffer=0x%08lx\n",
+        pr_debug("%s: %sing: block=%llu, sectors=%u\n",
                  drive->name, rq_data_dir(rq) == READ ? "read" : "writ",
-                 (unsigned long long)block, blk_rq_sectors(rq),
-                 (unsigned long)rq->buffer);
+                 (unsigned long long)block, blk_rq_sectors(rq));
 
         if (hwif->rw_disk)
                 hwif->rw_disk(drive, rq);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 455e64916498..6a71bc7c9133 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1544,7 +1544,6 @@ static int setup_clone(struct request *clone, struct request *rq,
         clone->cmd = rq->cmd;
         clone->cmd_len = rq->cmd_len;
         clone->sense = rq->sense;
-        clone->buffer = rq->buffer;
         clone->end_io = end_clone_request;
         clone->end_io_data = tio;
 
diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index 0b2ccb68c0d0..4dbfaee9aa95 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -82,8 +82,7 @@ static int do_blktrans_request(struct mtd_blktrans_ops *tr,
 
         block = blk_rq_pos(req) << 9 >> tr->blkshift;
         nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
-
-        buf = req->buffer;
+        buf = bio_data(req->bio);
 
         if (req->cmd_type != REQ_TYPE_FS)
                 return -EIO;
diff --git a/drivers/mtd/ubi/block.c b/drivers/mtd/ubi/block.c
index 7ff473c871a9..ee774ba3728d 100644
--- a/drivers/mtd/ubi/block.c
+++ b/drivers/mtd/ubi/block.c
@@ -253,7 +253,7 @@ static int do_ubiblock_request(struct ubiblock *dev, struct request *req)
          * flash access anyway.
          */
         mutex_lock(&dev->dev_mutex);
-        ret = ubiblock_read(dev, req->buffer, sec, len);
+        ret = ubiblock_read(dev, bio_data(req->bio), sec, len);
         mutex_unlock(&dev->dev_mutex);
 
         return ret;
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 0f3bddcb6b1a..3cc82d3dec78 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1018,8 +1018,6 @@ static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
                 return BLKPREP_DEFER;
         }
 
-        req->buffer = NULL;
-
         /* 
          * Next, walk the list, and fill in the addresses and sizes of
          * each segment.
@@ -1156,7 +1154,6 @@ int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
                 BUG_ON(blk_rq_bytes(req));
 
                 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
-                req->buffer = NULL;
         }
 
         cmd->cmd_len = req->cmd_len;
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index efcbcd182863..06d154d20faa 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -739,14 +739,11 @@ static int sd_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq)
 
         blk_add_request_payload(rq, page, len);
         ret = scsi_setup_blk_pc_cmnd(sdp, rq);
-        rq->buffer = page_address(page);
         rq->__data_len = nr_bytes;
 
 out:
-        if (ret != BLKPREP_OK) {
+        if (ret != BLKPREP_OK)
                 __free_page(page);
-                rq->buffer = NULL;
-        }
         return ret;
 }
 
@@ -843,8 +840,9 @@ static void sd_unprep_fn(struct request_queue *q, struct request *rq)
         struct scsi_cmnd *SCpnt = rq->special;
 
         if (rq->cmd_flags & REQ_DISCARD) {
-                free_page((unsigned long)rq->buffer);
-                rq->buffer = NULL;
+                struct bio *bio = rq->bio;
+
+                __free_page(bio->bi_io_vec->bv_page);
         }
         if (SCpnt->cmnd != rq->cmd) {
                 mempool_free(SCpnt->cmnd, sd_cdb_pool);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 86a8df13a5fe..eb5e94803892 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -178,7 +178,6 @@ struct request {
         unsigned short ioprio;
 
         void *special;          /* opaque pointer available for LLD use */
-        char *buffer;           /* kaddr of the current segment if available */
 
         int tag;
         int errors;