[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>

diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c
index ae41628..f52a78f 100644 (file)
--- 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)