[PATCH 1/2] disk: Add support for device-specific malloc function

[Leif Lindholm <leif.lindholm@linaro.org>]

Some disk types have allocation requirements beyond normal grub_malloc.
Add a function pointer to grub_disk_t and a wrapper function in
kern/disk.c making use of that function if available, to enable these
disk drivers to implement their own malloc.
---
 grub-core/kern/disk.c | 13 +++++++++++--
 include/grub/disk.h   |  5 +++++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/grub-core/kern/disk.c b/grub-core/kern/disk.c
index 789f8c0..e186586 100644
--- a/grub-core/kern/disk.c
+++ b/grub-core/kern/disk.c
@@ -184,6 +184,15 @@ find_part_sep (const char *name)
   return NULL;
 }
 
+static void *
+disk_malloc (struct grub_disk *disk, grub_size_t size)
+{
+  if (disk->malloc)
+    return disk->malloc (disk, size);
+
+  return grub_malloc (size);
+}
+
 grub_disk_t
 grub_disk_open (const char *name)
 {
@@ -331,7 +340,7 @@ grub_disk_read_small_real (grub_disk_t disk, grub_disk_addr_t sector,
     }
 
   /* Allocate a temporary buffer.  */
-  tmp_buf = grub_malloc (GRUB_DISK_SECTOR_SIZE << GRUB_DISK_CACHE_BITS);
+  tmp_buf = disk_malloc (disk, GRUB_DISK_SECTOR_SIZE << GRUB_DISK_CACHE_BITS);
   if (! tmp_buf)
     return grub_errno;
 
@@ -373,7 +382,7 @@ grub_disk_read_small_real (grub_disk_t disk, grub_disk_addr_t sector,
     num = ((size + offset + (1ULL << (disk->log_sector_size))
 	    - 1) >> (disk->log_sector_size));
 
-    tmp_buf = grub_malloc (num << disk->log_sector_size);
+    tmp_buf = disk_malloc (disk, num << disk->log_sector_size);
     if (!tmp_buf)
       return grub_errno;
     
diff --git a/include/grub/disk.h b/include/grub/disk.h
index b385af8..0fdd779 100644
--- a/include/grub/disk.h
+++ b/include/grub/disk.h
@@ -111,6 +111,8 @@ typedef void (*grub_disk_read_hook_t) (grub_disk_addr_t sector,
 				       unsigned offset, unsigned length,
 				       void *data);
 
+typedef void *(*grub_disk_malloc_t) (struct grub_disk *disk, grub_size_t size);
+
 /* Disk.  */
 struct grub_disk
 {
@@ -144,6 +146,9 @@ struct grub_disk
 
   /* Device-specific data.  */
   void *data;
+
+  /* Device-specific malloc function. */
+  grub_disk_malloc_t malloc;
 };
 typedef struct grub_disk *grub_disk_t;
 
-- 
2.1.4