From 5868287460b0fc243e828a0b856cd53d8bf45739 Mon Sep 17 00:00:00 2001 From: Robert Love Date: Tue, 3 Nov 2009 11:47:28 -0800 Subject: [PATCH] [SCSI] libfc: Add routine to copy data from a buffer to a SG list When handling the multi-frame responses of fc pass-thru requests, a code segment similar to fc_fcp_recv_data (routine to receive inbound SCSI data) is used in the response handler. This patch is to add a routine, called fc_copy_buffer_to_sglist(), to handle the common function of copying data from a buffer to a scatter- gather list in order to avoid code duplication. Signed-off-by: Robert Love Signed-off-by: James Bottomley --- drivers/scsi/libfc/fc_fcp.c | 56 ++++++-------------------------- drivers/scsi/libfc/fc_libfc.c | 60 +++++++++++++++++++++++++++++++++++ drivers/scsi/libfc/fc_libfc.h | 8 +++++ 3 files changed, 78 insertions(+), 46 deletions(-) diff --git a/drivers/scsi/libfc/fc_fcp.c b/drivers/scsi/libfc/fc_fcp.c index 866f78ac4ec2..98279fe0d0c7 100644 --- a/drivers/scsi/libfc/fc_fcp.c +++ b/drivers/scsi/libfc/fc_fcp.c @@ -323,7 +323,7 @@ static void fc_fcp_recv_data(struct fc_fcp_pkt *fsp, struct fc_frame *fp) size_t len; void *buf; struct scatterlist *sg; - size_t remaining; + u32 nents; fh = fc_frame_header_get(fp); offset = ntohl(fh->fh_parm_offset); @@ -347,55 +347,19 @@ static void fc_fcp_recv_data(struct fc_fcp_pkt *fsp, struct fc_frame *fp) if (offset != fsp->xfer_len) fsp->state |= FC_SRB_DISCONTIG; - crc = 0; - if (fr_flags(fp) & FCPHF_CRC_UNCHECKED) - crc = crc32(~0, (u8 *) fh, sizeof(*fh)); - sg = scsi_sglist(sc); - remaining = len; + nents = scsi_sg_count(sc); - while (remaining > 0 && sg) { - size_t off; - void *page_addr; - size_t sg_bytes; - - if (offset >= sg->length) { - offset -= sg->length; - sg = sg_next(sg); - continue; - } - sg_bytes = min(remaining, sg->length - offset); - - /* - * The scatterlist item may be bigger than PAGE_SIZE, - * but we are limited to mapping PAGE_SIZE at a time. - */ - off = offset + sg->offset; - sg_bytes = min(sg_bytes, (size_t) - (PAGE_SIZE - (off & ~PAGE_MASK))); - page_addr = kmap_atomic(sg_page(sg) + (off >> PAGE_SHIFT), - KM_SOFTIRQ0); - if (!page_addr) - break; /* XXX panic? */ - - if (fr_flags(fp) & FCPHF_CRC_UNCHECKED) - crc = crc32(crc, buf, sg_bytes); - memcpy((char *)page_addr + (off & ~PAGE_MASK), buf, - sg_bytes); - - kunmap_atomic(page_addr, KM_SOFTIRQ0); - buf += sg_bytes; - offset += sg_bytes; - remaining -= sg_bytes; - copy_len += sg_bytes; - } - - if (fr_flags(fp) & FCPHF_CRC_UNCHECKED) { + if (!(fr_flags(fp) & FCPHF_CRC_UNCHECKED)) { + copy_len = fc_copy_buffer_to_sglist(buf, len, sg, &nents, + &offset, KM_SOFTIRQ0, NULL); + } else { + crc = crc32(~0, (u8 *) fh, sizeof(*fh)); + copy_len = fc_copy_buffer_to_sglist(buf, len, sg, &nents, + &offset, KM_SOFTIRQ0, &crc); buf = fc_frame_payload_get(fp, 0); - if (len % 4) { + if (len % 4) crc = crc32(crc, buf + len, 4 - (len % 4)); - len += 4 - (len % 4); - } if (~crc != le32_to_cpu(fr_crc(fp))) { crc_err: diff --git a/drivers/scsi/libfc/fc_libfc.c b/drivers/scsi/libfc/fc_libfc.c index 01418ae8cb84..295eafb0316f 100644 --- a/drivers/scsi/libfc/fc_libfc.c +++ b/drivers/scsi/libfc/fc_libfc.c @@ -72,3 +72,63 @@ static void __exit libfc_exit(void) fc_destroy_rport(); } module_exit(libfc_exit); + +/** + * fc_copy_buffer_to_sglist() - This routine copies the data of a buffer + * into a scatter-gather list (SG list). + * + * @buf: pointer to the data buffer. + * @len: the byte-length of the data buffer. + * @sg: pointer to the pointer of the SG list. + * @nents: pointer to the remaining number of entries in the SG list. + * @offset: pointer to the current offset in the SG list. + * @km_type: dedicated page table slot type for kmap_atomic. + * @crc: pointer to the 32-bit crc value. + * If crc is NULL, CRC is not calculated. + */ +u32 fc_copy_buffer_to_sglist(void *buf, size_t len, + struct scatterlist *sg, + u32 *nents, size_t *offset, + enum km_type km_type, u32 *crc) +{ + size_t remaining = len; + u32 copy_len = 0; + + while (remaining > 0 && sg) { + size_t off, sg_bytes; + void *page_addr; + + if (*offset >= sg->length) { + /* + * Check for end and drop resources + * from the last iteration. + */ + if (!(*nents)) + break; + --(*nents); + *offset -= sg->length; + sg = sg_next(sg); + continue; + } + sg_bytes = min(remaining, sg->length - *offset); + + /* + * The scatterlist item may be bigger than PAGE_SIZE, + * but we are limited to mapping PAGE_SIZE at a time. + */ + off = *offset + sg->offset; + sg_bytes = min(sg_bytes, + (size_t)(PAGE_SIZE - (off & ~PAGE_MASK))); + page_addr = kmap_atomic(sg_page(sg) + (off >> PAGE_SHIFT), + km_type); + if (crc) + *crc = crc32(*crc, buf, sg_bytes); + memcpy((char *)page_addr + (off & ~PAGE_MASK), buf, sg_bytes); + kunmap_atomic(page_addr, km_type); + buf += sg_bytes; + *offset += sg_bytes; + remaining -= sg_bytes; + copy_len += sg_bytes; + } + return copy_len; +} diff --git a/drivers/scsi/libfc/fc_libfc.h b/drivers/scsi/libfc/fc_libfc.h index 0530149ac174..e4b5e9280cb0 100644 --- a/drivers/scsi/libfc/fc_libfc.h +++ b/drivers/scsi/libfc/fc_libfc.h @@ -101,4 +101,12 @@ void fc_destroy_fcp(void); */ const char *fc_els_resp_type(struct fc_frame *); +/* + * Copies a buffer into an sg list + */ +u32 fc_copy_buffer_to_sglist(void *buf, size_t len, + struct scatterlist *sg, + u32 *nents, size_t *offset, + enum km_type km_type, u32 *crc); + #endif /* _FC_LIBFC_H_ */