diff options
| author | Geert Uytterhoeven <geert@linux-m68k.org> | 2017-07-05 17:09:42 +0200 |
|---|---|---|
| committer | Ulf Hansson <ulf.hansson@linaro.org> | 2017-07-11 16:27:49 +0200 |
| commit | aab2ee03912be6e12bb5f4810be0b80a82168d3e (patch) | |
| tree | f6f30ccccfdcb24eb20586c6a84b3416cd040645 | |
| parent | 7432b49b54cd931743f0b6e9f652bc329e4a242a (diff) | |
mmc: block: Let MMC_IOC_MULTI_CMD return zero again for zero entries
With gcc 4.1.2:
drivers/mmc/core/block.c: In function ‘mmc_blk_ioctl_cmd_issue’:
drivers/mmc/core/block.c:630: warning: ‘ioc_err’ may be used uninitialized in this function
Indeed, if mq_rq->ioc_count is zero, an uninitialized value will be
stored in mq_rq->drv_op_result and passed to blk_end_request_all().
Can mq_rq->ioc_count be zero?
- mmc_blk_ioctl_cmd() sets ioc_count to 1, so this is safe,
- mmc_blk_ioctl_multi_cmd() obtains ioc_count from user space in
response to the MMC_IOC_MULTI_CMD ioctl, and does allow zero.
To avoid returning an uninitialized value, and as it is pointless to do
all this work when the MMC_IOC_MULTI_CMD ioctl is used with zero
entries, check for this early in mmc_blk_ioctl_multi_cmd(), and return
zero, like was returned before.
Fixes: 3ecd8cf23f88d5df ("mmc: block: move multi-ioctl() to use block layer")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
| -rw-r--r-- | drivers/mmc/core/block.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index 4920ea1ece38..e0363223996e 100644 --- a/drivers/mmc/core/block.c +++ b/drivers/mmc/core/block.c @@ -637,6 +637,9 @@ static int mmc_blk_ioctl_multi_cmd(struct block_device *bdev, sizeof(num_of_cmds))) return -EFAULT; + if (!num_of_cmds) + return 0; + if (num_of_cmds > MMC_IOC_MAX_CMDS) return -EINVAL; |