scsi: sd: Use sysfs_match_string()

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 <Bart.VanAssche@sandisk.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 53b6d72c214d65c7ca3b911c76b66697397f77c5..7dc8cb8f1818049245f5e5ddd918757997128974 100644 (file)
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -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];
@@ -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;
 
@@ -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
@@ -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
@@ -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);
 
@@ -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);
 
@@ -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
@@ -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);
 
@@ -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);
 
@@ -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",
@@ -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
@@ -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;
@@ -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",
@@ -432,7 +422,7 @@ 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
@@ -440,21 +430,17 @@ 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);
@@ -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
@@ -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
@@ -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);