diff options
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/storage/protocol.c | 126 |
1 files changed, 53 insertions, 73 deletions
diff --git a/drivers/usb/storage/protocol.c b/drivers/usb/storage/protocol.c index 889622baac2..a41ce21c069 100644 --- a/drivers/usb/storage/protocol.c +++ b/drivers/usb/storage/protocol.c @@ -149,11 +149,7 @@ void usb_stor_transparent_scsi_command(struct scsi_cmnd *srb, ***********************************************************************/ /* Copy a buffer of length buflen to/from the srb's transfer buffer. - * (Note: for scatter-gather transfers (srb->use_sg > 0), srb->request_buffer - * points to a list of s-g entries and we ignore srb->request_bufflen. - * For non-scatter-gather transfers, srb->request_buffer points to the - * transfer buffer itself and srb->request_bufflen is the buffer's length.) - * Update the *index and *offset variables so that the next copy will + * Update the **sgptr and *offset variables so that the next copy will * pick up from where this one left off. */ unsigned int usb_stor_access_xfer_buf(unsigned char *buffer, @@ -162,80 +158,64 @@ unsigned int usb_stor_access_xfer_buf(unsigned char *buffer, { unsigned int cnt; - /* If not using scatter-gather, just transfer the data directly. - * Make certain it will fit in the available buffer space. */ - if (srb->use_sg == 0) { - if (*offset >= srb->request_bufflen) - return 0; - cnt = min(buflen, srb->request_bufflen - *offset); - if (dir == TO_XFER_BUF) - memcpy((unsigned char *) srb->request_buffer + *offset, - buffer, cnt); - else - memcpy(buffer, (unsigned char *) srb->request_buffer + - *offset, cnt); - *offset += cnt; - - /* Using scatter-gather. We have to go through the list one entry + /* We have to go through the list one entry * at a time. Each s-g entry contains some number of pages, and * each page has to be kmap()'ed separately. If the page is already * in kernel-addressable memory then kmap() will return its address. * If the page is not directly accessible -- such as a user 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 = *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) { - struct page *page = sg_page(sg) + - ((sg->offset + *offset) >> PAGE_SHIFT); - unsigned int poff = - (sg->offset + *offset) & (PAGE_SIZE-1); - unsigned int sglen = sg->length - *offset; - - if (sglen > buflen - cnt) { - - /* Transfer ends within this s-g entry */ - sglen = buflen - cnt; - *offset += sglen; - } else { - - /* Transfer continues to next s-g entry */ - *offset = 0; - sg = sg_next(sg); - } - - /* Transfer the data for all the pages in this - * s-g entry. For each page: call kmap(), do the - * transfer, and call kunmap() immediately after. */ - while (sglen > 0) { - unsigned int plen = min(sglen, (unsigned int) - PAGE_SIZE - poff); - unsigned char *ptr = kmap(page); - - if (dir == TO_XFER_BUF) - memcpy(ptr + poff, buffer + cnt, plen); - else - memcpy(buffer + cnt, ptr + poff, plen); - kunmap(page); - - /* Start at the beginning of the next page */ - poff = 0; - ++page; - cnt += plen; - sglen -= plen; - } + struct scatterlist *sg = *sgptr; + + if (!sg) + sg = scsi_sglist(srb); + + /* 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 **sgptr values for the next loop. */ + cnt = 0; + while (cnt < buflen) { + struct page *page = sg_page(sg) + + ((sg->offset + *offset) >> PAGE_SHIFT); + unsigned int poff = + (sg->offset + *offset) & (PAGE_SIZE-1); + unsigned int sglen = sg->length - *offset; + + if (sglen > buflen - cnt) { + + /* Transfer ends within this s-g entry */ + sglen = buflen - cnt; + *offset += sglen; + } else { + + /* Transfer continues to next s-g entry */ + *offset = 0; + sg = sg_next(sg); + } + + /* Transfer the data for all the pages in this + * s-g entry. For each page: call kmap(), do the + * transfer, and call kunmap() immediately after. */ + while (sglen > 0) { + unsigned int plen = min(sglen, (unsigned int) + PAGE_SIZE - poff); + unsigned char *ptr = kmap(page); + + if (dir == TO_XFER_BUF) + memcpy(ptr + poff, buffer + cnt, plen); + else + memcpy(buffer + cnt, ptr + poff, plen); + kunmap(page); + + /* Start at the beginning of the next page */ + poff = 0; + ++page; + cnt += plen; + sglen -= plen; } - *sgptr = sg; } + *sgptr = sg; /* Return the amount actually transferred */ return cnt; @@ -251,6 +231,6 @@ void usb_stor_set_xfer_buf(unsigned char *buffer, usb_stor_access_xfer_buf(buffer, buflen, srb, &sg, &offset, TO_XFER_BUF); - if (buflen < srb->request_bufflen) - srb->resid = srb->request_bufflen - buflen; + if (buflen < scsi_bufflen(srb)) + scsi_set_resid(srb, scsi_bufflen(srb) - buflen); } |