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scsi: sd: Use sysfs_match_string()
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Avoid unnecessary snprintf() when formatting variables for display in
sysfs and switch to sysfs_match_string() for validating user input.

Reviewed-by: Bart Van Assche <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
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@martinkpetersen
martinkpetersen committed Jun 26, 2017
1 parent 6934be4 commit 4c11712
Showing 1 changed file with 29 additions and 42 deletions.
71 changes: 29 additions & 42 deletions drivers/scsi/sd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -155,7 +155,7 @@ static ssize_t
cache_type_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
int i, ct = -1, rcd, wce, sp;
int ct, rcd, wce, sp;
struct scsi_disk *sdkp = to_scsi_disk(dev);
struct scsi_device *sdp = sdkp->device;
char buffer[64];
Expand All @@ -178,16 +178,10 @@ cache_type_store(struct device *dev, struct device_attribute *attr,
sdkp->cache_override = 0;
}

for (i = 0; i < ARRAY_SIZE(sd_cache_types); i++) {
len = strlen(sd_cache_types[i]);
if (strncmp(sd_cache_types[i], buf, len) == 0 &&
buf[len] == '\n') {
ct = i;
break;
}
}
ct = sysfs_match_string(sd_cache_types, buf);
if (ct < 0)
return -EINVAL;

rcd = ct & 0x01 ? 1 : 0;
wce = (ct & 0x02) && !sdkp->write_prot ? 1 : 0;

Expand Down Expand Up @@ -227,7 +221,7 @@ manage_start_stop_show(struct device *dev, struct device_attribute *attr,
struct scsi_disk *sdkp = to_scsi_disk(dev);
struct scsi_device *sdp = sdkp->device;

return snprintf(buf, 20, "%u\n", sdp->manage_start_stop);
return sprintf(buf, "%u\n", sdp->manage_start_stop);
}

static ssize_t
Expand All @@ -251,7 +245,7 @@ allow_restart_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct scsi_disk *sdkp = to_scsi_disk(dev);

return snprintf(buf, 40, "%d\n", sdkp->device->allow_restart);
return sprintf(buf, "%u\n", sdkp->device->allow_restart);
}

static ssize_t
Expand Down Expand Up @@ -279,7 +273,7 @@ cache_type_show(struct device *dev, struct device_attribute *attr, char *buf)
struct scsi_disk *sdkp = to_scsi_disk(dev);
int ct = sdkp->RCD + 2*sdkp->WCE;

return snprintf(buf, 40, "%s\n", sd_cache_types[ct]);
return sprintf(buf, "%s\n", sd_cache_types[ct]);
}
static DEVICE_ATTR_RW(cache_type);

Expand All @@ -288,7 +282,7 @@ FUA_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct scsi_disk *sdkp = to_scsi_disk(dev);

return snprintf(buf, 20, "%u\n", sdkp->DPOFUA);
return sprintf(buf, "%u\n", sdkp->DPOFUA);
}
static DEVICE_ATTR_RO(FUA);

Expand All @@ -298,7 +292,7 @@ protection_type_show(struct device *dev, struct device_attribute *attr,
{
struct scsi_disk *sdkp = to_scsi_disk(dev);

return snprintf(buf, 20, "%u\n", sdkp->protection_type);
return sprintf(buf, "%u\n", sdkp->protection_type);
}

static ssize_t
Expand Down Expand Up @@ -341,9 +335,9 @@ protection_mode_show(struct device *dev, struct device_attribute *attr,
}

if (!dif && !dix)
return snprintf(buf, 20, "none\n");
return sprintf(buf, "none\n");

return snprintf(buf, 20, "%s%u\n", dix ? "dix" : "dif", dif);
return sprintf(buf, "%s%u\n", dix ? "dix" : "dif", dif);
}
static DEVICE_ATTR_RO(protection_mode);

Expand All @@ -352,7 +346,7 @@ app_tag_own_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct scsi_disk *sdkp = to_scsi_disk(dev);

return snprintf(buf, 20, "%u\n", sdkp->ATO);
return sprintf(buf, "%u\n", sdkp->ATO);
}
static DEVICE_ATTR_RO(app_tag_own);

Expand All @@ -362,10 +356,11 @@ thin_provisioning_show(struct device *dev, struct device_attribute *attr,
{
struct scsi_disk *sdkp = to_scsi_disk(dev);

return snprintf(buf, 20, "%u\n", sdkp->lbpme);
return sprintf(buf, "%u\n", sdkp->lbpme);
}
static DEVICE_ATTR_RO(thin_provisioning);

/* sysfs_match_string() requires dense arrays */
static const char *lbp_mode[] = {
[SD_LBP_FULL] = "full",
[SD_LBP_UNMAP] = "unmap",
Expand All @@ -381,7 +376,7 @@ provisioning_mode_show(struct device *dev, struct device_attribute *attr,
{
struct scsi_disk *sdkp = to_scsi_disk(dev);

return snprintf(buf, 20, "%s\n", lbp_mode[sdkp->provisioning_mode]);
return sprintf(buf, "%s\n", lbp_mode[sdkp->provisioning_mode]);
}

static ssize_t
Expand All @@ -390,6 +385,7 @@ provisioning_mode_store(struct device *dev, struct device_attribute *attr,
{
struct scsi_disk *sdkp = to_scsi_disk(dev);
struct scsi_device *sdp = sdkp->device;
int mode;

if (!capable(CAP_SYS_ADMIN))
return -EACCES;
Expand All @@ -402,23 +398,17 @@ provisioning_mode_store(struct device *dev, struct device_attribute *attr,
if (sdp->type != TYPE_DISK)
return -EINVAL;

if (!strncmp(buf, lbp_mode[SD_LBP_UNMAP], 20))
sd_config_discard(sdkp, SD_LBP_UNMAP);
else if (!strncmp(buf, lbp_mode[SD_LBP_WS16], 20))
sd_config_discard(sdkp, SD_LBP_WS16);
else if (!strncmp(buf, lbp_mode[SD_LBP_WS10], 20))
sd_config_discard(sdkp, SD_LBP_WS10);
else if (!strncmp(buf, lbp_mode[SD_LBP_ZERO], 20))
sd_config_discard(sdkp, SD_LBP_ZERO);
else if (!strncmp(buf, lbp_mode[SD_LBP_DISABLE], 20))
sd_config_discard(sdkp, SD_LBP_DISABLE);
else
mode = sysfs_match_string(lbp_mode, buf);
if (mode < 0)
return -EINVAL;

sd_config_discard(sdkp, mode);

return count;
}
static DEVICE_ATTR_RW(provisioning_mode);

/* sysfs_match_string() requires dense arrays */
static const char *zeroing_mode[] = {
[SD_ZERO_WRITE] = "write",
[SD_ZERO_WS] = "writesame",
Expand All @@ -432,29 +422,25 @@ zeroing_mode_show(struct device *dev, struct device_attribute *attr,
{
struct scsi_disk *sdkp = to_scsi_disk(dev);

return snprintf(buf, 20, "%s\n", zeroing_mode[sdkp->zeroing_mode]);
return sprintf(buf, "%s\n", zeroing_mode[sdkp->zeroing_mode]);
}

static ssize_t
zeroing_mode_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct scsi_disk *sdkp = to_scsi_disk(dev);
int mode;

if (!capable(CAP_SYS_ADMIN))
return -EACCES;

if (!strncmp(buf, zeroing_mode[SD_ZERO_WRITE], 20))
sdkp->zeroing_mode = SD_ZERO_WRITE;
else if (!strncmp(buf, zeroing_mode[SD_ZERO_WS], 20))
sdkp->zeroing_mode = SD_ZERO_WS;
else if (!strncmp(buf, zeroing_mode[SD_ZERO_WS16_UNMAP], 20))
sdkp->zeroing_mode = SD_ZERO_WS16_UNMAP;
else if (!strncmp(buf, zeroing_mode[SD_ZERO_WS10_UNMAP], 20))
sdkp->zeroing_mode = SD_ZERO_WS10_UNMAP;
else
mode = sysfs_match_string(zeroing_mode, buf);
if (mode < 0)
return -EINVAL;

sdkp->zeroing_mode = mode;

return count;
}
static DEVICE_ATTR_RW(zeroing_mode);
Expand All @@ -465,7 +451,7 @@ max_medium_access_timeouts_show(struct device *dev,
{
struct scsi_disk *sdkp = to_scsi_disk(dev);

return snprintf(buf, 20, "%u\n", sdkp->max_medium_access_timeouts);
return sprintf(buf, "%u\n", sdkp->max_medium_access_timeouts);
}

static ssize_t
Expand All @@ -491,7 +477,7 @@ max_write_same_blocks_show(struct device *dev, struct device_attribute *attr,
{
struct scsi_disk *sdkp = to_scsi_disk(dev);

return snprintf(buf, 20, "%u\n", sdkp->max_ws_blocks);
return sprintf(buf, "%u\n", sdkp->max_ws_blocks);
}

static ssize_t
Expand Down Expand Up @@ -696,6 +682,7 @@ static void sd_config_discard(struct scsi_disk *sdkp, unsigned int mode)

switch (mode) {

case SD_LBP_FULL:
case SD_LBP_DISABLE:
blk_queue_max_discard_sectors(q, 0);
queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
Expand Down

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