1 files changed, 207 insertions, 63 deletions

diff --git a/fs/bio.c b/fs/bio.c
index 3a1472acc361..83a349574567 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -25,6 +25,7 @@
 #include <linux/module.h>
 #include <linux/mempool.h>
 #include <linux/workqueue.h>
+#include <scsi/sg.h>            /* for struct sg_iovec */
 
 #define BIO_POOL_SIZE 256
 
@@ -52,7 +53,7 @@ struct biovec_slab {
  */
 
 #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
-static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] = {
+static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
         BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
 };
 #undef BV
@@ -104,18 +105,22 @@ static inline struct bio_vec *bvec_alloc_bs(unsigned int __nocast gfp_mask, int
         return bvl;
 }
 
-/*
- * default destructor for a bio allocated with bio_alloc_bioset()
- */
-static void bio_destructor(struct bio *bio)
+void bio_free(struct bio *bio, struct bio_set *bio_set)
 {
         const int pool_idx = BIO_POOL_IDX(bio);
-        struct bio_set *bs = bio->bi_set;
 
         BIO_BUG_ON(pool_idx >= BIOVEC_NR_POOLS);
 
-        mempool_free(bio->bi_io_vec, bs->bvec_pools[pool_idx]);
-        mempool_free(bio, bs->bio_pool);
+        mempool_free(bio->bi_io_vec, bio_set->bvec_pools[pool_idx]);
+        mempool_free(bio, bio_set->bio_pool);
+}
+
+/*
+ * default destructor for a bio allocated with bio_alloc_bioset()
+ */
+static void bio_fs_destructor(struct bio *bio)
+{
+        bio_free(bio, fs_bio_set);
 }
 
 inline void bio_init(struct bio *bio)
@@ -171,8 +176,6 @@ struct bio *bio_alloc_bioset(unsigned int __nocast gfp_mask, int nr_iovecs, stru
                         bio->bi_max_vecs = bvec_slabs[idx].nr_vecs;
                 }
                 bio->bi_io_vec = bvl;
-                bio->bi_destructor = bio_destructor;
-                bio->bi_set = bs;
         }
 out:
         return bio;
@@ -180,7 +183,12 @@ out:
 
 struct bio *bio_alloc(unsigned int __nocast gfp_mask, int nr_iovecs)
 {
-        return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
+        struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
+
+        if (bio)
+                bio->bi_destructor = bio_fs_destructor;
+
+        return bio;
 }
 
 void zero_fill_bio(struct bio *bio)
@@ -248,19 +256,16 @@ inline void __bio_clone(struct bio *bio, struct bio *bio_src)
 {
         request_queue_t *q = bdev_get_queue(bio_src->bi_bdev);
 
-        memcpy(bio->bi_io_vec, bio_src->bi_io_vec, bio_src->bi_max_vecs * sizeof(struct bio_vec));
+        memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
+                bio_src->bi_max_vecs * sizeof(struct bio_vec));
 
         bio->bi_sector = bio_src->bi_sector;
         bio->bi_bdev = bio_src->bi_bdev;
         bio->bi_flags |= 1 << BIO_CLONED;
         bio->bi_rw = bio_src->bi_rw;
-
-        /*
-         * notes -- maybe just leave bi_idx alone. assume identical mapping
-         * for the clone
-         */
         bio->bi_vcnt = bio_src->bi_vcnt;
         bio->bi_size = bio_src->bi_size;
+        bio->bi_idx = bio_src->bi_idx;
         bio_phys_segments(q, bio);
         bio_hw_segments(q, bio);
 }
@@ -276,8 +281,10 @@ struct bio *bio_clone(struct bio *bio, unsigned int __nocast gfp_mask)
 {
         struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set);
 
-        if (b)
+        if (b) {
+                b->bi_destructor = bio_fs_destructor;
                 __bio_clone(b, bio);
+        }
 
         return b;
 }
@@ -549,22 +556,34 @@ out_bmd:
         return ERR_PTR(ret);
 }
 
-static struct bio *__bio_map_user(request_queue_t *q, struct block_device *bdev,
-                                  unsigned long uaddr, unsigned int len,
-                                  int write_to_vm)
+static struct bio *__bio_map_user_iov(request_queue_t *q,
+                                      struct block_device *bdev,
+                                      struct sg_iovec *iov, int iov_count,
+                                      int write_to_vm)
 {
-        unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
-        unsigned long start = uaddr >> PAGE_SHIFT;
-        const int nr_pages = end - start;
-        int ret, offset, i;
+        int i, j;
+        int nr_pages = 0;
         struct page **pages;
         struct bio *bio;
+        int cur_page = 0;
+        int ret, offset;
 
-        /*
-         * transfer and buffer must be aligned to at least hardsector
-         * size for now, in the future we can relax this restriction
-         */
-        if ((uaddr & queue_dma_alignment(q)) || (len & queue_dma_alignment(q)))
+        for (i = 0; i < iov_count; i++) {
+                unsigned long uaddr = (unsigned long)iov[i].iov_base;
+                unsigned long len = iov[i].iov_len;
+                unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+                unsigned long start = uaddr >> PAGE_SHIFT;
+
+                nr_pages += end - start;
+                /*
+                 * transfer and buffer must be aligned to at least hardsector
+                 * size for now, in the future we can relax this restriction
+                 */
+                if ((uaddr & queue_dma_alignment(q)) || (len & queue_dma_alignment(q)))
+                        return ERR_PTR(-EINVAL);
+        }
+
+        if (!nr_pages)
                 return ERR_PTR(-EINVAL);
 
         bio = bio_alloc(GFP_KERNEL, nr_pages);
@@ -576,42 +595,54 @@ static struct bio *__bio_map_user(request_queue_t *q, struct block_device *bdev,
         if (!pages)
                 goto out;
 
-        down_read(&current->mm->mmap_sem);
-        ret = get_user_pages(current, current->mm, uaddr, nr_pages,
-                                                write_to_vm, 0, pages, NULL);
-        up_read(&current->mm->mmap_sem);
-
-        if (ret < nr_pages)
-                goto out;
-
-        bio->bi_bdev = bdev;
-
-        offset = uaddr & ~PAGE_MASK;
-        for (i = 0; i < nr_pages; i++) {
-                unsigned int bytes = PAGE_SIZE - offset;
-
-                if (len <= 0)
-                        break;
-
-                if (bytes > len)
-                        bytes = len;
+        memset(pages, 0, nr_pages * sizeof(struct page *));
+
+        for (i = 0; i < iov_count; i++) {
+                unsigned long uaddr = (unsigned long)iov[i].iov_base;
+                unsigned long len = iov[i].iov_len;
+                unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+                unsigned long start = uaddr >> PAGE_SHIFT;
+                const int local_nr_pages = end - start;
+                const int page_limit = cur_page + local_nr_pages;
+                
+                down_read(&current->mm->mmap_sem);
+                ret = get_user_pages(current, current->mm, uaddr,
+                                     local_nr_pages,
+                                     write_to_vm, 0, &pages[cur_page], NULL);
+                up_read(&current->mm->mmap_sem);
+
+                if (ret < local_nr_pages)
+                        goto out_unmap;
+
+
+                offset = uaddr & ~PAGE_MASK;
+                for (j = cur_page; j < page_limit; j++) {
+                        unsigned int bytes = PAGE_SIZE - offset;
+
+                        if (len <= 0)
+                                break;
+                        
+                        if (bytes > len)
+                                bytes = len;
+
+                        /*
+                         * sorry...
+                         */
+                        if (__bio_add_page(q, bio, pages[j], bytes, offset) < bytes)
+                                break;
+
+                        len -= bytes;
+                        offset = 0;
+                }
 
+                cur_page = j;
                 /*
-                 * sorry...
+                 * release the pages we didn't map into the bio, if any
                  */
-                if (__bio_add_page(q, bio, pages[i], bytes, offset) < bytes)
-                        break;
-
-                len -= bytes;
-                offset = 0;
+                while (j < page_limit)
+                        page_cache_release(pages[j++]);
         }
 
-        /*
-         * release the pages we didn't map into the bio, if any
-         */
-        while (i < nr_pages)
-                page_cache_release(pages[i++]);
-
         kfree(pages);
 
         /*
@@ -620,9 +651,17 @@ static struct bio *__bio_map_user(request_queue_t *q, struct block_device *bdev,
         if (!write_to_vm)
                 bio->bi_rw |= (1 << BIO_RW);
 
+        bio->bi_bdev = bdev;
         bio->bi_flags |= (1 << BIO_USER_MAPPED);
         return bio;
-out:
+
+ out_unmap:
+        for (i = 0; i < nr_pages; i++) {
+                if(!pages[i])
+                        break;
+                page_cache_release(pages[i]);
+        }
+ out:
         kfree(pages);
         bio_put(bio);
         return ERR_PTR(ret);
@@ -642,9 +681,33 @@ out:
 struct bio *bio_map_user(request_queue_t *q, struct block_device *bdev,
                          unsigned long uaddr, unsigned int len, int write_to_vm)
 {
+        struct sg_iovec iov;
+
+        iov.iov_base = (void __user *)uaddr;
+        iov.iov_len = len;
+
+        return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm);
+}
+
+/**
+ *      bio_map_user_iov - map user sg_iovec table into bio
+ *      @q: the request_queue_t for the bio
+ *      @bdev: destination block device
+ *      @iov:   the iovec.
+ *      @iov_count: number of elements in the iovec
+ *      @write_to_vm: bool indicating writing to pages or not
+ *
+ *      Map the user space address into a bio suitable for io to a block
+ *      device. Returns an error pointer in case of error.
+ */
+struct bio *bio_map_user_iov(request_queue_t *q, struct block_device *bdev,
+                             struct sg_iovec *iov, int iov_count,
+                             int write_to_vm)
+{
         struct bio *bio;
+        int len = 0, i;
 
-        bio = __bio_map_user(q, bdev, uaddr, len, write_to_vm);
+        bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm);
 
         if (IS_ERR(bio))
                 return bio;
@@ -657,6 +720,9 @@ struct bio *bio_map_user(request_queue_t *q, struct block_device *bdev,
          */
         bio_get(bio);
 
+        for (i = 0; i < iov_count; i++)
+                len += iov[i].iov_len;
+
         if (bio->bi_size == len)
                 return bio;
 
@@ -701,6 +767,82 @@ void bio_unmap_user(struct bio *bio)
         bio_put(bio);
 }
 
+static int bio_map_kern_endio(struct bio *bio, unsigned int bytes_done, int err)
+{
+        if (bio->bi_size)
+                return 1;
+
+        bio_put(bio);
+        return 0;
+}
+
+
+static struct bio *__bio_map_kern(request_queue_t *q, void *data,
+                                  unsigned int len, unsigned int gfp_mask)
+{
+        unsigned long kaddr = (unsigned long)data;
+        unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+        unsigned long start = kaddr >> PAGE_SHIFT;
+        const int nr_pages = end - start;
+        int offset, i;
+        struct bio *bio;
+
+        bio = bio_alloc(gfp_mask, nr_pages);
+        if (!bio)
+                return ERR_PTR(-ENOMEM);
+
+        offset = offset_in_page(kaddr);
+        for (i = 0; i < nr_pages; i++) {
+                unsigned int bytes = PAGE_SIZE - offset;
+
+                if (len <= 0)
+                        break;
+
+                if (bytes > len)
+                        bytes = len;
+
+                if (__bio_add_page(q, bio, virt_to_page(data), bytes,
+                                   offset) < bytes)
+                        break;
+
+                data += bytes;
+                len -= bytes;
+                offset = 0;
+        }
+
+        bio->bi_end_io = bio_map_kern_endio;
+        return bio;
+}
+
+/**
+ *      bio_map_kern    -       map kernel address into bio
+ *      @q: the request_queue_t for the bio
+ *      @data: pointer to buffer to map
+ *      @len: length in bytes
+ *      @gfp_mask: allocation flags for bio allocation
+ *
+ *      Map the kernel address into a bio suitable for io to a block
+ *      device. Returns an error pointer in case of error.
+ */
+struct bio *bio_map_kern(request_queue_t *q, void *data, unsigned int len,
+                         unsigned int gfp_mask)
+{
+        struct bio *bio;
+
+        bio = __bio_map_kern(q, data, len, gfp_mask);
+        if (IS_ERR(bio))
+                return bio;
+
+        if (bio->bi_size == len)
+                return bio;
+
+        /*
+         * Don't support partial mappings.
+         */
+        bio_put(bio);
+        return ERR_PTR(-EINVAL);
+}
+
 /*
  * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
  * for performing direct-IO in BIOs.
@@ -1078,6 +1220,7 @@ subsys_initcall(init_bio);
 
 EXPORT_SYMBOL(bio_alloc);
 EXPORT_SYMBOL(bio_put);
+EXPORT_SYMBOL(bio_free);
 EXPORT_SYMBOL(bio_endio);
 EXPORT_SYMBOL(bio_init);
 EXPORT_SYMBOL(__bio_clone);
@@ -1088,6 +1231,7 @@ EXPORT_SYMBOL(bio_add_page);
 EXPORT_SYMBOL(bio_get_nr_vecs);
 EXPORT_SYMBOL(bio_map_user);
 EXPORT_SYMBOL(bio_unmap_user);
+EXPORT_SYMBOL(bio_map_kern);
 EXPORT_SYMBOL(bio_pair_release);
 EXPORT_SYMBOL(bio_split);
 EXPORT_SYMBOL(bio_split_pool);