NVMe: Handle failures from memory allocations in nvme_setup_prps

If any of the memory allocations in nvme_setup_prps fail, handle it by
modifying the passed-in data length to reflect the number of bytes we are
actually able to send.  Also allow the caller to specify the GFP flags
they need; for user-initiated commands, we can use GFP_KERNEL allocations.

The various callers are updated to handle this possibility; the main
I/O path is already prepared for this possibility (as it may happen
due to nvme_map_bio being unable to map all the segments of the I/O).
The other callers return -ENOMEM instead of doing partial I/Os.

Reported-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

1 files changed, 41 insertions, 15 deletions

diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c
index 79012c53ae9c..ddc21ba24a70 100644
--- a/drivers/block/nvme.c
+++ b/drivers/block/nvme.c
@@ -329,9 +329,11 @@ static void bio_completion(struct nvme_queue *nvmeq, void *ctx,
 /* length is in bytes */
 static struct nvme_prps *nvme_setup_prps(struct nvme_dev *dev,
                                         struct nvme_common_command *cmd,
-                                        struct scatterlist *sg, int length)
+                                        struct scatterlist *sg, int *len,
+                                        gfp_t gfp)
 {
         struct dma_pool *pool;
+        int length = *len;
         int dma_len = sg_dma_len(sg);
         u64 dma_addr = sg_dma_address(sg);
         int offset = offset_in_page(dma_addr);
@@ -361,7 +363,12 @@ static struct nvme_prps *nvme_setup_prps(struct nvme_dev *dev,
 
         nprps = DIV_ROUND_UP(length, PAGE_SIZE);
         npages = DIV_ROUND_UP(8 * nprps, PAGE_SIZE);
-        prps = kmalloc(sizeof(*prps) + sizeof(__le64 *) * npages, GFP_ATOMIC);
+        prps = kmalloc(sizeof(*prps) + sizeof(__le64 *) * npages, gfp);
+        if (!prps) {
+                cmd->prp2 = cpu_to_le64(dma_addr);
+                *len = (*len - length) + PAGE_SIZE;
+                return prps;
+        }
         prp_page = 0;
         if (nprps <= (256 / 8)) {
                 pool = dev->prp_small_pool;
@@ -371,7 +378,13 @@ static struct nvme_prps *nvme_setup_prps(struct nvme_dev *dev,
                 prps->npages = npages;
         }
 
-        prp_list = dma_pool_alloc(pool, GFP_ATOMIC, &prp_dma);
+        prp_list = dma_pool_alloc(pool, gfp, &prp_dma);
+        if (!prp_list) {
+                cmd->prp2 = cpu_to_le64(dma_addr);
+                *len = (*len - length) + PAGE_SIZE;
+                kfree(prps);
+                return NULL;
+        }
         prps->list[prp_page++] = prp_list;
         prps->first_dma = prp_dma;
         cmd->prp2 = cpu_to_le64(prp_dma);
@@ -379,7 +392,11 @@ static struct nvme_prps *nvme_setup_prps(struct nvme_dev *dev,
         for (;;) {
                 if (i == PAGE_SIZE / 8) {
                         __le64 *old_prp_list = prp_list;
-                        prp_list = dma_pool_alloc(pool, GFP_ATOMIC, &prp_dma);
+                        prp_list = dma_pool_alloc(pool, gfp, &prp_dma);
+                        if (!prp_list) {
+                                *len = (*len - length);
+                                return prps;
+                        }
                         prps->list[prp_page++] = prp_list;
                         prp_list[0] = old_prp_list[i - 1];
                         old_prp_list[i - 1] = cpu_to_le64(prp_dma);
@@ -525,7 +542,7 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
         cmnd->rw.command_id = cmdid;
         cmnd->rw.nsid = cpu_to_le32(ns->ns_id);
         nbio->prps = nvme_setup_prps(nvmeq->dev, &cmnd->common, nbio->sg,
-                                                                length);
+                                                        &length, GFP_ATOMIC);
         cmnd->rw.slba = cpu_to_le64(bio->bi_sector >> (ns->lba_shift - 9));
         cmnd->rw.length = cpu_to_le16((length >> ns->lba_shift) - 1);
         cmnd->rw.control = cpu_to_le16(control);
@@ -1009,15 +1026,18 @@ static int nvme_submit_user_admin_command(struct nvme_dev *dev,
                                         unsigned long addr, unsigned length,
                                         struct nvme_command *cmd)
 {
-        int err, nents;
+        int err, nents, tmplen = length;
         struct scatterlist *sg;
         struct nvme_prps *prps;
 
         nents = nvme_map_user_pages(dev, 0, addr, length, &sg);
         if (nents < 0)
                 return nents;
-        prps = nvme_setup_prps(dev, &cmd->common, sg, length);
-        err = nvme_submit_admin_cmd(dev, cmd, NULL);
+        prps = nvme_setup_prps(dev, &cmd->common, sg, &tmplen, GFP_KERNEL);
+        if (tmplen != length)
+                err = -ENOMEM;
+        else
+                err = nvme_submit_admin_cmd(dev, cmd, NULL);
         nvme_unmap_user_pages(dev, 0, addr, length, sg, nents);
         nvme_free_prps(dev, prps);
         return err ? -EIO : 0;
@@ -1086,7 +1106,7 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
         c.rw.apptag = io.apptag;
         c.rw.appmask = io.appmask;
         /* XXX: metadata */
-        prps = nvme_setup_prps(dev, &c.common, sg, length);
+        prps = nvme_setup_prps(dev, &c.common, sg, &length, GFP_KERNEL);
 
         nvmeq = get_nvmeq(ns);
         /*
@@ -1096,7 +1116,10 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
          * additional races since q_lock already protects against other CPUs.
          */
         put_nvmeq(nvmeq);
-        status = nvme_submit_sync_cmd(nvmeq, &c, NULL, IO_TIMEOUT);
+        if (length != (io.nblocks + 1) << ns->lba_shift)
+                status = -ENOMEM;
+        else
+                status = nvme_submit_sync_cmd(nvmeq, &c, NULL, IO_TIMEOUT);
 
         nvme_unmap_user_pages(dev, io.opcode & 1, io.addr, length, sg, nents);
         nvme_free_prps(dev, prps);
@@ -1109,7 +1132,7 @@ static int nvme_download_firmware(struct nvme_ns *ns,
         struct nvme_dev *dev = ns->dev;
         struct nvme_dlfw dlfw;
         struct nvme_command c;
-        int nents, status;
+        int nents, status, length;
         struct scatterlist *sg;
         struct nvme_prps *prps;
 
@@ -1117,8 +1140,9 @@ static int nvme_download_firmware(struct nvme_ns *ns,
                 return -EFAULT;
         if (dlfw.length >= (1 << 30))
                 return -EINVAL;
+        length = dlfw.length * 4;
 
-        nents = nvme_map_user_pages(dev, 1, dlfw.addr, dlfw.length * 4, &sg);
+        nents = nvme_map_user_pages(dev, 1, dlfw.addr, length, &sg);
         if (nents < 0)
                 return nents;
 
@@ -1126,9 +1150,11 @@ static int nvme_download_firmware(struct nvme_ns *ns,
         c.dlfw.opcode = nvme_admin_download_fw;
         c.dlfw.numd = cpu_to_le32(dlfw.length);
         c.dlfw.offset = cpu_to_le32(dlfw.offset);
-        prps = nvme_setup_prps(dev, &c.common, sg, dlfw.length * 4);
-
-        status = nvme_submit_admin_cmd(dev, &c, NULL);
+        prps = nvme_setup_prps(dev, &c.common, sg, &length, GFP_KERNEL);
+        if (length != dlfw.length * 4)
+                status = -ENOMEM;
+        else
+                status = nvme_submit_admin_cmd(dev, &c, NULL);
         nvme_unmap_user_pages(dev, 0, dlfw.addr, dlfw.length * 4, sg, nents);
         nvme_free_prps(dev, prps);
         return status;