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mmc: block: copy resp[] data on err for MMC_IOC_MULTI_CMD

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MMC_IOC_CMD and MMC_IOC_MULTI_CMD ioctl() code currently bails on
any eMMC errors. However, in case there is any resp[] data, we
should attempt to copy resp[] back to user space. The user app
can then determine which command(s) failed in the MMC_IOC_MULTI_CMD
case AND/OR report better diagnostics in both cases.

Gwendal Grignou provided the idea and it was previously implemented
and tested on v3.18 ChromeOS kernel:
    https://chromium-review.googlesource.com/#/c/299956

Signed-off-by: Grant Grundler <grundler@chromium.org>
Reviewed-by: Hyung Taek Ryoo <hryoo@nvidia.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Tested-by: David Riley <davidriley@chromium.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Grant Grundler 2015-09-23 18:30:33 -07:00 committed by Ulf Hansson
parent 85f45058ee
commit b093410c9a
1 changed files with 9 additions and 18 deletions
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27
drivers/mmc/card/block.c
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@ -595,7 +595,7 @@ static int mmc_blk_ioctl_cmd(struct block_device *bdev,
struct mmc_blk_ioc_data *idata;
struct mmc_blk_data *md;
struct mmc_card *card;
int err;
int err = 0, ioc_err = 0;
idata = mmc_blk_ioctl_copy_from_user(ic_ptr);
if (IS_ERR(idata))
@ -615,19 +615,18 @@ static int mmc_blk_ioctl_cmd(struct block_device *bdev,
mmc_get_card(card);
err = __mmc_blk_ioctl_cmd(card, md, idata);
ioc_err = __mmc_blk_ioctl_cmd(card, md, idata);
mmc_put_card(card);
if (!err)
err = mmc_blk_ioctl_copy_to_user(ic_ptr, idata);
err = mmc_blk_ioctl_copy_to_user(ic_ptr, idata);
cmd_done:
mmc_blk_put(md);
cmd_err:
kfree(idata->buf);
kfree(idata);
return err;
return ioc_err ? ioc_err : err;
}
static int mmc_blk_ioctl_multi_cmd(struct block_device *bdev,
@ -637,7 +636,7 @@ static int mmc_blk_ioctl_multi_cmd(struct block_device *bdev,
struct mmc_ioc_cmd __user *cmds = user->cmds;
struct mmc_card *card;
struct mmc_blk_data *md;
int i, err = -EFAULT;
int i, err = 0, ioc_err = 0;
__u64 num_of_cmds;
if (copy_from_user(&num_of_cmds, &user->num_of_cmds,
@ -672,22 +671,14 @@ static int mmc_blk_ioctl_multi_cmd(struct block_device *bdev,
mmc_get_card(card);
for (i = 0; i < num_of_cmds; i++) {
err = __mmc_blk_ioctl_cmd(card, md, idata[i]);
if (err) {
mmc_put_card(card);
goto cmd_done;
}
}
for (i = 0; i < num_of_cmds && !ioc_err; i++)
ioc_err = __mmc_blk_ioctl_cmd(card, md, idata[i]);
mmc_put_card(card);
/* copy to user if data and response */
for (i = 0; i < num_of_cmds; i++) {
for (i = 0; i < num_of_cmds && !err; i++)
err = mmc_blk_ioctl_copy_to_user(&cmds[i], idata[i]);
if (err)
break;
}
cmd_done:
mmc_blk_put(md);
@ -697,7 +688,7 @@ cmd_err:
kfree(idata[i]);
}
kfree(idata);
return err;
return ioc_err ? ioc_err : err;
}
static int mmc_blk_ioctl(struct block_device *bdev, fmode_t mode,