[PATCH] dm mirror log: refactor context

Refactor the code that creates the core and disk log contexts to avoid the
repeated allocation of clean_bits introduced by the last patch.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 63 insertions, 50 deletions

diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c
index ae41628b75c0..f52a78fc82bb 100644
--- a/drivers/md/dm-log.c
+++ b/drivers/md/dm-log.c
@@ -244,15 +244,16 @@ static inline int write_header(struct log_c *log)
  * argv contains region_size followed optionally by [no]sync
  *--------------------------------------------------------------*/
 #define BYTE_SHIFT 3
-static int core_ctr(struct dirty_log *log, struct dm_target *ti,
-                    unsigned int argc, char **argv)
+static int create_log_context(struct dirty_log *log, struct dm_target *ti,
+                              unsigned int argc, char **argv,
+                              struct dm_dev *dev)
 {
         enum sync sync = DEFAULTSYNC;
 
         struct log_c *lc;
         uint32_t region_size;
         unsigned int region_count;
-        size_t bitset_size;
+        size_t bitset_size, buf_size;
 
         if (argc < 1 || argc > 2) {
                 DMWARN("wrong number of arguments to mirror log");
@@ -298,18 +299,49 @@ static int core_ctr(struct dirty_log *log, struct dm_target *ti,
         bitset_size >>= BYTE_SHIFT;
 
         lc->bitset_uint32_count = bitset_size / 4;
-        lc->clean_bits = vmalloc(bitset_size);
-        if (!lc->clean_bits) {
-                DMWARN("couldn't allocate clean bitset");
-                kfree(lc);
-                return -ENOMEM;
+
+        /*
+         * Disk log?
+         */
+        if (!dev) {
+                lc->clean_bits = vmalloc(bitset_size);
+                if (!lc->clean_bits) {
+                        DMWARN("couldn't allocate clean bitset");
+                        kfree(lc);
+                        return -ENOMEM;
+                }
+                lc->disk_header = NULL;
+        } else {
+                lc->log_dev = dev;
+                lc->header_location.bdev = lc->log_dev->bdev;
+                lc->header_location.sector = 0;
+
+                /*
+                 * Buffer holds both header and bitset.
+                 */
+                buf_size = dm_round_up((LOG_OFFSET << SECTOR_SHIFT) +
+                                       bitset_size, ti->limits.hardsect_size);
+                lc->header_location.count = buf_size >> SECTOR_SHIFT;
+
+                lc->disk_header = vmalloc(buf_size);
+                if (!lc->disk_header) {
+                        DMWARN("couldn't allocate disk log buffer");
+                        kfree(lc);
+                        return -ENOMEM;
+                }
+
+                lc->clean_bits = (void *)lc->disk_header +
+                                 (LOG_OFFSET << SECTOR_SHIFT);
         }
+
         memset(lc->clean_bits, -1, bitset_size);
 
         lc->sync_bits = vmalloc(bitset_size);
         if (!lc->sync_bits) {
                 DMWARN("couldn't allocate sync bitset");
-                vfree(lc->clean_bits);
+                if (!dev)
+                        vfree(lc->clean_bits);
+                vfree(lc->disk_header);
                 kfree(lc);
                 return -ENOMEM;
         }
@@ -320,25 +352,40 @@ static int core_ctr(struct dirty_log *log, struct dm_target *ti,
         if (!lc->recovering_bits) {
                 DMWARN("couldn't allocate sync bitset");
                 vfree(lc->sync_bits);
-                vfree(lc->clean_bits);
+                if (!dev)
+                        vfree(lc->clean_bits);
+                vfree(lc->disk_header);
                 kfree(lc);
                 return -ENOMEM;
         }
         memset(lc->recovering_bits, 0, bitset_size);
         lc->sync_search = 0;
         log->context = lc;
+
         return 0;
 }
 
-static void core_dtr(struct dirty_log *log)
+static int core_ctr(struct dirty_log *log, struct dm_target *ti,
+                    unsigned int argc, char **argv)
+{
+        return create_log_context(log, ti, argc, argv, NULL);
+}
+
+static void destroy_log_context(struct log_c *lc)
 {
-        struct log_c *lc = (struct log_c *) log->context;
-        vfree(lc->clean_bits);
         vfree(lc->sync_bits);
         vfree(lc->recovering_bits);
         kfree(lc);
 }
 
+static void core_dtr(struct dirty_log *log)
+{
+        struct log_c *lc = (struct log_c *) log->context;
+
+        vfree(lc->clean_bits);
+        destroy_log_context(lc);
+}
+
 /*----------------------------------------------------------------
  * disk log constructor/destructor
  *
@@ -348,10 +395,7 @@ static int disk_ctr(struct dirty_log *log, struct dm_target *ti,
                     unsigned int argc, char **argv)
 {
         int r;
-        size_t size, bitset_size;
-        struct log_c *lc;
         struct dm_dev *dev;
-        uint32_t *clean_bits;
 
         if (argc < 2 || argc > 3) {
                 DMWARN("wrong number of arguments to disk mirror log");
@@ -363,53 +407,22 @@ static int disk_ctr(struct dirty_log *log, struct dm_target *ti,
         if (r)
                 return r;
 
-        r = core_ctr(log, ti, argc - 1, argv + 1);
+        r = create_log_context(log, ti, argc - 1, argv + 1, dev);
         if (r) {
                 dm_put_device(ti, dev);
                 return r;
         }
 
-        lc = (struct log_c *) log->context;
-        lc->log_dev = dev;
-
-        /* setup the disk header fields */
-        lc->header_location.bdev = lc->log_dev->bdev;
-        lc->header_location.sector = 0;
-
-        /* Include both the header and the bitset in one buffer. */
-        bitset_size = lc->bitset_uint32_count * sizeof(uint32_t);
-        size = dm_round_up((LOG_OFFSET << SECTOR_SHIFT) + bitset_size,
-                           ti->limits.hardsect_size);
-        lc->header_location.count = size >> SECTOR_SHIFT;
-
-        lc->disk_header = vmalloc(size);
-        if (!lc->disk_header)
-                goto bad;
-
-        /*
-         * Deallocate the clean_bits buffer that was allocated in core_ctr()
-         * and point it at the appropriate place in the disk_header buffer.
-         */
-        clean_bits = lc->clean_bits;
-        lc->clean_bits = (void *)lc->disk_header + (LOG_OFFSET << SECTOR_SHIFT);
-        memcpy(lc->clean_bits, clean_bits, bitset_size);
-        vfree(clean_bits);
-
         return 0;
-
- bad:
-        dm_put_device(ti, lc->log_dev);
-        core_dtr(log);
-        return -ENOMEM;
 }
 
 static void disk_dtr(struct dirty_log *log)
 {
         struct log_c *lc = (struct log_c *) log->context;
+
         dm_put_device(lc->ti, lc->log_dev);
         vfree(lc->disk_header);
-        lc->clean_bits = NULL;
-        core_dtr(log);
+        destroy_log_context(lc);
 }
 
 static int count_bits32(uint32_t *addr, unsigned size)