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path: root/drivers/usb/storage/protocol.c
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Diffstat (limited to 'drivers/usb/storage/protocol.c')
-rw-r--r--drivers/usb/storage/protocol.c20
1 files changed, 11 insertions, 9 deletions
diff --git a/drivers/usb/storage/protocol.c b/drivers/usb/storage/protocol.c
index 9ad30428d2d..cc8f7c52c72 100644
--- a/drivers/usb/storage/protocol.c
+++ b/drivers/usb/storage/protocol.c
@@ -157,7 +157,7 @@ void usb_stor_transparent_scsi_command(struct scsi_cmnd *srb,
* pick up from where this one left off. */
unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
- unsigned int buflen, struct scsi_cmnd *srb, unsigned int *index,
+ unsigned int buflen, struct scsi_cmnd *srb, struct scatterlist **sgptr,
unsigned int *offset, enum xfer_buf_dir dir)
{
unsigned int cnt;
@@ -184,16 +184,17 @@ unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
* located in high memory -- then kmap() will map it to a temporary
* position in the kernel's virtual address space. */
} else {
- struct scatterlist *sg =
- (struct scatterlist *) srb->request_buffer
- + *index;
+ struct scatterlist *sg = *sgptr;
+
+ if (!sg)
+ sg = (struct scatterlist *) srb->request_buffer;
/* This loop handles a single s-g list entry, which may
* include multiple pages. Find the initial page structure
* and the starting offset within the page, and update
* the *offset and *index values for the next loop. */
cnt = 0;
- while (cnt < buflen && *index < srb->use_sg) {
+ while (cnt < buflen) {
struct page *page = sg->page +
((sg->offset + *offset) >> PAGE_SHIFT);
unsigned int poff =
@@ -209,8 +210,7 @@ unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
/* Transfer continues to next s-g entry */
*offset = 0;
- ++*index;
- ++sg;
+ sg = sg_next(sg);
}
/* Transfer the data for all the pages in this
@@ -234,6 +234,7 @@ unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
sglen -= plen;
}
}
+ *sgptr = sg;
}
/* Return the amount actually transferred */
@@ -245,9 +246,10 @@ unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
void usb_stor_set_xfer_buf(unsigned char *buffer,
unsigned int buflen, struct scsi_cmnd *srb)
{
- unsigned int index = 0, offset = 0;
+ unsigned int offset = 0;
+ struct scatterlist *sg = NULL;
- usb_stor_access_xfer_buf(buffer, buflen, srb, &index, &offset,
+ usb_stor_access_xfer_buf(buffer, buflen, srb, &sg, &offset,
TO_XFER_BUF);
if (buflen < srb->request_bufflen)
srb->resid = srb->request_bufflen - buflen;