[PATCH AUTOSEL 5.8 113/132] scsi: core: Clean up allocation and freeing of sgtables

Sasha Levin
2020-10-27T00:01:27Z

From: Christoph Hellwig <hch@lst.de>

[ Upstream commit 7007e9dd56767a95de0947b3f7599bcc2f21687f ]

Rename scsi_init_io() to scsi_alloc_sgtables(), and ensure callers call
scsi_free_sgtables() to cleanup failures close to scsi_init_io() instead of
leaking it down the generic I/O submission path.

Link: https://lore.kernel.org/r/20201005084130.143273-9-hch@lst.de
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/scsi_lib.c | 22 ++++++++--------------
drivers/scsi/sd.c | 27 +++++++++++++++------------
drivers/scsi/sr.c | 16 ++++++----------
include/scsi/scsi_cmnd.h | 3 ++-
4 files changed, 31 insertions(+), 37 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index ae620dada8ce5..ba8fafd24f4bd 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -531,7 +531,7 @@ static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
}
}

-static void scsi_free_sgtables(struct scsi_cmnd *cmd)
+void scsi_free_sgtables(struct scsi_cmnd *cmd)
{
if (cmd->sdb.table.nents)
sg_free_table_chained(&cmd->sdb.table,
@@ -540,6 +540,7 @@ static void scsi_free_sgtables(struct scsi_cmnd *cmd)
sg_free_table_chained(&cmd->prot_sdb->table,
SCSI_INLINE_PROT_SG_CNT);
}
+EXPORT_SYMBOL_GPL(scsi_free_sgtables);

static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
{
@@ -967,7 +968,7 @@ static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
}

/**
- * scsi_init_io - SCSI I/O initialization function.
+ * scsi_alloc_sgtables - allocate S/G tables for a command
* @cmd: command descriptor we wish to initialize
*
* Returns:
@@ -975,7 +976,7 @@ static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
* * BLK_STS_RESOURCE - if the failure is retryable
* * BLK_STS_IOERR - if the failure is fatal
*/
-blk_status_t scsi_init_io(struct scsi_cmnd *cmd)
+blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
{
struct scsi_device *sdev = cmd->device;
struct request *rq = cmd->request;
@@ -1067,7 +1068,7 @@ blk_status_t scsi_init_io(struct scsi_cmnd *cmd)
scsi_free_sgtables(cmd);
return ret;
}
-EXPORT_SYMBOL(scsi_init_io);
+EXPORT_SYMBOL(scsi_alloc_sgtables);

/**
* scsi_initialize_rq - initialize struct scsi_cmnd partially
@@ -1155,7 +1156,7 @@ static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
* submit a request without an attached bio.
*/
if (req->bio) {
- blk_status_t ret = scsi_init_io(cmd);
+ blk_status_t ret = scsi_alloc_sgtables(cmd);
if (unlikely(ret != BLK_STS_OK))
return ret;
} else {
@@ -1195,7 +1196,6 @@ static blk_status_t scsi_setup_cmnd(struct scsi_device *sdev,
struct request *req)
{
struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
- blk_status_t ret;

if (!blk_rq_bytes(req))
cmd->sc_data_direction = DMA_NONE;
@@ -1205,14 +1205,8 @@ static blk_status_t scsi_setup_cmnd(struct scsi_device *sdev,
cmd->sc_data_direction = DMA_FROM_DEVICE;

if (blk_rq_is_scsi(req))
- ret = scsi_setup_scsi_cmnd(sdev, req);
- else
- ret = scsi_setup_fs_cmnd(sdev, req);
-
- if (ret != BLK_STS_OK)
- scsi_free_sgtables(cmd);
-
- return ret;
+ return scsi_setup_scsi_cmnd(sdev, req);
+ return scsi_setup_fs_cmnd(sdev, req);
}

static blk_status_t
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 4b2117cb84837..c0c422ad305bc 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -866,7 +866,7 @@ static blk_status_t sd_setup_unmap_cmnd(struct scsi_cmnd *cmd)
cmd->transfersize = data_len;
rq->timeout = SD_TIMEOUT;

- return scsi_init_io(cmd);
+ return scsi_alloc_sgtables(cmd);
}

static blk_status_t sd_setup_write_same16_cmnd(struct scsi_cmnd *cmd,
@@ -897,7 +897,7 @@ static blk_status_t sd_setup_write_same16_cmnd(struct scsi_cmnd *cmd,
cmd->transfersize = data_len;
rq->timeout = unmap ? SD_TIMEOUT : SD_WRITE_SAME_TIMEOUT;

- return scsi_init_io(cmd);
+ return scsi_alloc_sgtables(cmd);
}

static blk_status_t sd_setup_write_same10_cmnd(struct scsi_cmnd *cmd,
@@ -928,7 +928,7 @@ static blk_status_t sd_setup_write_same10_cmnd(struct scsi_cmnd *cmd,
cmd->transfersize = data_len;
rq->timeout = unmap ? SD_TIMEOUT : SD_WRITE_SAME_TIMEOUT;

- return scsi_init_io(cmd);
+ return scsi_alloc_sgtables(cmd);
}

static blk_status_t sd_setup_write_zeroes_cmnd(struct scsi_cmnd *cmd)
@@ -1069,7 +1069,7 @@ static blk_status_t sd_setup_write_same_cmnd(struct scsi_cmnd *cmd)
* knows how much to actually write.
*/
rq->__data_len = sdp->sector_size;
- ret = scsi_init_io(cmd);
+ ret = scsi_alloc_sgtables(cmd);
rq->__data_len = blk_rq_bytes(rq);

return ret;
@@ -1187,23 +1187,24 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *cmd)
unsigned int dif;
bool dix;

- ret = scsi_init_io(cmd);
+ ret = scsi_alloc_sgtables(cmd);
if (ret != BLK_STS_OK)
return ret;

+ ret = BLK_STS_IOERR;
if (!scsi_device_online(sdp) || sdp->changed) {
scmd_printk(KERN_ERR, cmd, "device offline or changed\n");
- return BLK_STS_IOERR;
+ goto fail;
}

if (blk_rq_pos(rq) + blk_rq_sectors(rq) > get_capacity(rq->rq_disk)) {
scmd_printk(KERN_ERR, cmd, "access beyond end of device\n");
- return BLK_STS_IOERR;
+ goto fail;
}

if ((blk_rq_pos(rq) & mask) || (blk_rq_sectors(rq) & mask)) {
scmd_printk(KERN_ERR, cmd, "request not aligned to the logical block size\n");
- return BLK_STS_IOERR;
+ goto fail;
}

/*
@@ -1225,7 +1226,7 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *cmd)
if (req_op(rq) == REQ_OP_ZONE_APPEND) {
ret = sd_zbc_prepare_zone_append(cmd, &lba, nr_blocks);
if (ret)
- return ret;
+ goto fail;
}

fua = rq->cmd_flags & REQ_FUA ? 0x8 : 0;
@@ -1253,7 +1254,7 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *cmd)
}

if (unlikely(ret != BLK_STS_OK))
- return ret;
+ goto fail;

/*
* We shouldn't disconnect in the middle of a sector, so with a dumb
@@ -1277,10 +1278,12 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *cmd)
blk_rq_sectors(rq)));

/*
- * This indicates that the command is ready from our end to be
- * queued.
+ * This indicates that the command is ready from our end to be queued.
*/
return BLK_STS_OK;
+fail:
+ scsi_free_sgtables(cmd);
+ return ret;
}

static blk_status_t sd_init_command(struct scsi_cmnd *cmd)
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 0c4aa4665a2f9..b74dfd8dc1165 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -392,15 +392,11 @@ static blk_status_t sr_init_command(struct scsi_cmnd *SCpnt)
struct request *rq = SCpnt->request;
blk_status_t ret;

- ret = scsi_init_io(SCpnt);
+ ret = scsi_alloc_sgtables(SCpnt);
if (ret != BLK_STS_OK)
- goto out;
+ return ret;
cd = scsi_cd(rq->rq_disk);

- /* from here on until we're complete, any goto out
- * is used for a killable error condition */
- ret = BLK_STS_IOERR;
-
SCSI_LOG_HLQUEUE(1, scmd_printk(KERN_INFO, SCpnt,
"Doing sr request, block = %d\n", block));

@@ -509,12 +505,12 @@ static blk_status_t sr_init_command(struct scsi_cmnd *SCpnt)
SCpnt->allowed = MAX_RETRIES;

/*
- * This indicates that the command is ready from our end to be
- * queued.
+ * This indicates that the command is ready from our end to be queued.
*/
- ret = BLK_STS_OK;
+ return BLK_STS_OK;
out:
- return ret;
+ scsi_free_sgtables(SCpnt);
+ return BLK_STS_IOERR;
}

static int sr_block_open(struct block_device *bdev, fmode_t mode)
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index e76bac4d14c51..69ade4fb71aab 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -165,7 +165,8 @@ extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
size_t *offset, size_t *len);
extern void scsi_kunmap_atomic_sg(void *virt);

-extern blk_status_t scsi_init_io(struct scsi_cmnd *cmd);
+blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd);
+void scsi_free_sgtables(struct scsi_cmnd *cmd);

#ifdef CONFIG_SCSI_DMA
extern int scsi_dma_map(struct scsi_cmnd *cmd);
--
2.25.1