ChangeSet 1.1504.2.12, 2003/12/08 17:44:31-08:00, [EMAIL PROTECTED]
[PATCH] USB storage: Remove unneeded scatter-gather operations in sddr09
This patch removes some unnecessary scatter-gather code from the sddr09
driver. In its place a single smaller buffer is re-used each time through
an I/O loop, as opposed to transferring all the data at once.
Andries Brouwer kindly tested this and suggested some improvements to get
it working right.
drivers/usb/storage/sddr09.c | 112 ++++++++++++++++---------------------------
1 files changed, 42 insertions(+), 70 deletions(-)
diff -Nru a/drivers/usb/storage/sddr09.c b/drivers/usb/storage/sddr09.c
--- a/drivers/usb/storage/sddr09.c Mon Dec 29 14:25:42 2003
+++ b/drivers/usb/storage/sddr09.c Mon Dec 29 14:25:42 2003
@@ -1092,69 +1092,33 @@
static int
sddr09_read_map(struct us_data *us) {
- struct scatterlist *sg;
struct sddr09_card_info *info = (struct sddr09_card_info *) us->extra;
int numblocks, alloc_len, alloc_blocks;
int i, j, result;
- unsigned char *ptr;
+ unsigned char *buffer, *buffer_end, *ptr;
unsigned int lba, lbact;
if (!info->capacity)
return -1;
- // read 64 (1<<6) bytes for every block
- // ( 1 << ( blockshift + pageshift ) bytes)
- // of capacity:
- // (1<<6)*capacity/(1<<(b+p)) =
- // ((1<<6)*capacity)>>(b+p) =
- // capacity>>(b+p-6)
-
- alloc_len = info->capacity >>
- (info->blockshift + info->pageshift - CONTROL_SHIFT);
-
- // Allocate a number of scatterlist structures according to
- // the number of 128k blocks in the alloc_len. Adding 128k-1
- // and then dividing by 128k gives the correct number of blocks.
- // 128k = 1<<17
-
- alloc_blocks = (alloc_len + (1<<17) - 1) >> 17;
- sg = kmalloc(alloc_blocks*sizeof(struct scatterlist),
- GFP_NOIO);
- if (sg == NULL)
- return 0;
-
- for (i=0; i<alloc_blocks; i++) {
- int alloc_req = (i < alloc_blocks-1 ? 1 << 17 : alloc_len);
- char *vaddr = kmalloc(alloc_req, GFP_NOIO);
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,3)
- sg[i].page = virt_to_page(vaddr);
- sg[i].offset = offset_in_page(vaddr);
-#else
- sg[i].address = vaddr;
-#endif
- sg[i].length = alloc_req;
- alloc_len -= alloc_req;
- }
-
- for (i=0; i<alloc_blocks; i++)
- if (sg[i].page == NULL) {
- for (i=0; i<alloc_blocks; i++)
- if (sg[i].page != NULL)
- kfree(sg_address(sg[i]));
- kfree(sg);
- return 0;
- }
+ // size of a block is 1 << (blockshift + pageshift) bytes
+ // divide into the total capacity to get the number of blocks
numblocks = info->capacity >> (info->blockshift + info->pageshift);
- result = sddr09_read_control(us, 0, numblocks,
- (unsigned char *)sg, alloc_blocks);
- if (result != USB_STOR_TRANSPORT_GOOD) {
- for (i=0; i<alloc_blocks; i++)
- kfree(sg_address(sg[i]));
- kfree(sg);
- return -1;
- }
+ // read 64 bytes for every block (actually 1 << CONTROL_SHIFT)
+ // but only use a 64 KB buffer
+ // buffer size used must be a multiple of (1 << CONTROL_SHIFT)
+#define SDDR09_READ_MAP_BUFSZ 65536
+
+ alloc_blocks = min(numblocks, SDDR09_READ_MAP_BUFSZ >> CONTROL_SHIFT);
+ alloc_len = (alloc_blocks << CONTROL_SHIFT);
+ buffer = kmalloc(alloc_len, GFP_NOIO);
+ if (buffer == NULL)
+ return 0;
+ buffer_end = buffer + alloc_len;
+
+#undef SDDR09_READ_MAP_BUFSZ
kfree(info->lba_to_pba);
kfree(info->pba_to_lba);
@@ -1162,29 +1126,31 @@
info->pba_to_lba = kmalloc(numblocks*sizeof(int), GFP_NOIO);
if (info->lba_to_pba == NULL || info->pba_to_lba == NULL) {
- kfree(info->lba_to_pba);
- kfree(info->pba_to_lba);
- info->lba_to_pba = NULL;
- info->pba_to_lba = NULL;
- for (i=0; i<alloc_blocks; i++)
- kfree(sg_address(sg[i]));
- kfree(sg);
- return 0;
+ result = -1;
+ goto done;
}
for (i = 0; i < numblocks; i++)
info->lba_to_pba[i] = info->pba_to_lba[i] = UNDEF;
- ptr = sg_address(sg[0]);
-
/*
* Define lba-pba translation table
*/
- // Each block is 64 bytes of control data, so block i is located in
- // scatterlist block i*64/128k = i*(2^6)*(2^-17) = i*(2^-11)
- for (i=0; i<numblocks; i++) {
- ptr = sg_address(sg[i>>11]) + ((i&0x7ff)<<6);
+ ptr = buffer_end;
+ for (i = 0; i < numblocks; i++) {
+ ptr += (1 << CONTROL_SHIFT);
+ if (ptr >= buffer_end) {
+ ptr = buffer;
+ result = sddr09_read_control(
+ us, i << (info->blockshift + 8),
+ min(alloc_blocks, numblocks - i),
+ buffer, 0);
+ if (result != USB_STOR_TRANSPORT_GOOD) {
+ result = -1;
+ goto done;
+ }
+ }
if (i == 0 || i == 1) {
info->pba_to_lba[i] = UNUSABLE;
@@ -1292,11 +1258,17 @@
}
info->lbact = lbact;
US_DEBUGP("Found %d LBA's\n", lbact);
+ result = 0;
- for (i=0; i<alloc_blocks; i++)
- kfree(sg_address(sg[i]));
- kfree(sg);
- return 0;
+ done:
+ if (result != 0) {
+ kfree(info->lba_to_pba);
+ kfree(info->pba_to_lba);
+ info->lba_to_pba = NULL;
+ info->pba_to_lba = NULL;
+ }
+ kfree(buffer);
+ return result;
}
static void
-------------------------------------------------------
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