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Date: Mon, 23 Mar 2015 20:52:15 +0000
From: Long Li <longli@...rosoft.com>
To: KY Srinivasan <kys@...rosoft.com>,
"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"devel@...uxdriverproject.org" <devel@...uxdriverproject.org>,
"ohering@...e.com" <ohering@...e.com>,
"jbottomley@...allels.com" <jbottomley@...allels.com>,
"hch@...radead.org" <hch@...radead.org>,
"linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
"apw@...onical.com" <apw@...onical.com>,
"vkuznets@...hat.com" <vkuznets@...hat.com>,
"jasowang@...hat.com" <jasowang@...hat.com>
Subject: RE: [PATCH 6/7] scsi: storvsc: Don't assume that the scatterlist is
not chained
> -----Original Message-----
> From: devel [mailto:driverdev-devel-bounces@...uxdriverproject.org] On
> Behalf Of K. Y. Srinivasan
> Sent: Monday, March 23, 2015 2:07 PM
> To: gregkh@...uxfoundation.org; linux-kernel@...r.kernel.org;
> devel@...uxdriverproject.org; ohering@...e.com; jbottomley@...allels.com;
> hch@...radead.org; linux-scsi@...r.kernel.org; apw@...onical.com;
> vkuznets@...hat.com; jasowang@...hat.com
> Subject: [PATCH 6/7] scsi: storvsc: Don't assume that the scatterlist is not
> chained
>
> The current code assumes that the scatterlists presented are not chained.
> Fix the code to not make this assumption.
>
> Signed-off-by: K. Y. Srinivasan <kys@...rosoft.com>
Reviewed-by: Long Li <longli@...rosoft.com>
> ---
> drivers/scsi/storvsc_drv.c | 98 +++++++++++++++++++++++++------------------
> 1 files changed, 57 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index
> 88f5d79..a599677 100644
> --- a/drivers/scsi/storvsc_drv.c
> +++ b/drivers/scsi/storvsc_drv.c
> @@ -626,19 +626,6 @@ cleanup:
> return NULL;
> }
>
> -/* Disgusting wrapper functions */
> -static inline unsigned long sg_kmap_atomic(struct scatterlist *sgl, int idx) -{
> - void *addr = kmap_atomic(sg_page(sgl + idx));
> - return (unsigned long)addr;
> -}
> -
> -static inline void sg_kunmap_atomic(unsigned long addr) -{
> - kunmap_atomic((void *)addr);
> -}
> -
> -
> /* Assume the original sgl has enough room */ static unsigned int
> copy_from_bounce_buffer(struct scatterlist *orig_sgl,
> struct scatterlist *bounce_sgl, @@ -
> 653,32 +640,39 @@ static unsigned int copy_from_bounce_buffer(struct
> scatterlist *orig_sgl,
> unsigned long bounce_addr = 0;
> unsigned long dest_addr = 0;
> unsigned long flags;
> + struct scatterlist *cur_dest_sgl;
> + struct scatterlist *cur_src_sgl;
>
> local_irq_save(flags);
> -
> + cur_dest_sgl = orig_sgl;
> + cur_src_sgl = bounce_sgl;
> for (i = 0; i < orig_sgl_count; i++) {
> - dest_addr = sg_kmap_atomic(orig_sgl,i) + orig_sgl[i].offset;
> + dest_addr = (unsigned long)
> + kmap_atomic(sg_page(cur_dest_sgl)) +
> + cur_dest_sgl->offset;
> dest = dest_addr;
> destlen = orig_sgl[i].length;
> + destlen = cur_dest_sgl->length;
>
> if (bounce_addr == 0)
> - bounce_addr = sg_kmap_atomic(bounce_sgl,j);
> + bounce_addr = (unsigned long)kmap_atomic(
> + sg_page(cur_src_sgl));
>
> while (destlen) {
> - src = bounce_addr + bounce_sgl[j].offset;
> - srclen = bounce_sgl[j].length - bounce_sgl[j].offset;
> + src = bounce_addr + cur_src_sgl->offset;
> + srclen = cur_src_sgl->length - cur_src_sgl->offset;
>
> copylen = min(srclen, destlen);
> memcpy((void *)dest, (void *)src, copylen);
>
> total_copied += copylen;
> - bounce_sgl[j].offset += copylen;
> + cur_src_sgl->offset += copylen;
> destlen -= copylen;
> dest += copylen;
>
> - if (bounce_sgl[j].offset == bounce_sgl[j].length) {
> + if (cur_src_sgl->offset == cur_src_sgl->length) {
> /* full */
> - sg_kunmap_atomic(bounce_addr);
> + kunmap_atomic((void *)bounce_addr);
> j++;
>
> /*
> @@ -692,21 +686,27 @@ static unsigned int copy_from_bounce_buffer(struct
> scatterlist *orig_sgl,
> /*
> * We are done; cleanup and return.
> */
> - sg_kunmap_atomic(dest_addr -
> orig_sgl[i].offset);
> + kunmap_atomic((void *)(dest_addr -
> + cur_dest_sgl->offset));
> local_irq_restore(flags);
> return total_copied;
> }
>
> /* if we need to use another bounce buffer */
> - if (destlen || i != orig_sgl_count - 1)
> - bounce_addr =
> sg_kmap_atomic(bounce_sgl,j);
> + if (destlen || i != orig_sgl_count - 1) {
> + cur_src_sgl = sg_next(cur_src_sgl);
> + bounce_addr = (unsigned long)
> + kmap_atomic(
> + sg_page(cur_src_sgl));
> + }
> } else if (destlen == 0 && i == orig_sgl_count - 1) {
> /* unmap the last bounce that is < PAGE_SIZE
> */
> - sg_kunmap_atomic(bounce_addr);
> + kunmap_atomic((void *)bounce_addr);
> }
> }
>
> - sg_kunmap_atomic(dest_addr - orig_sgl[i].offset);
> + kunmap_atomic((void *)(dest_addr - cur_dest_sgl->offset));
> + cur_dest_sgl = sg_next(cur_dest_sgl);
> }
>
> local_irq_restore(flags);
> @@ -727,48 +727,61 @@ static unsigned int copy_to_bounce_buffer(struct
> scatterlist *orig_sgl,
> unsigned long bounce_addr = 0;
> unsigned long src_addr = 0;
> unsigned long flags;
> + struct scatterlist *cur_src_sgl;
> + struct scatterlist *cur_dest_sgl;
>
> local_irq_save(flags);
>
> + cur_src_sgl = orig_sgl;
> + cur_dest_sgl = bounce_sgl;
> +
> for (i = 0; i < orig_sgl_count; i++) {
> - src_addr = sg_kmap_atomic(orig_sgl,i) + orig_sgl[i].offset;
> + src_addr = (unsigned long)
> + kmap_atomic(sg_page(cur_src_sgl)) +
> + cur_src_sgl->offset;
> src = src_addr;
> - srclen = orig_sgl[i].length;
> + srclen = cur_src_sgl->length;
>
> if (bounce_addr == 0)
> - bounce_addr = sg_kmap_atomic(bounce_sgl,j);
> + bounce_addr = (unsigned long)
> + kmap_atomic(sg_page(cur_dest_sgl));
>
> while (srclen) {
> /* assume bounce offset always == 0 */
> - dest = bounce_addr + bounce_sgl[j].length;
> - destlen = PAGE_SIZE - bounce_sgl[j].length;
> + dest = bounce_addr + cur_dest_sgl->length;
> + destlen = PAGE_SIZE - cur_dest_sgl->length;
>
> copylen = min(srclen, destlen);
> memcpy((void *)dest, (void *)src, copylen);
>
> total_copied += copylen;
> - bounce_sgl[j].length += copylen;
> + cur_dest_sgl->length += copylen;
> srclen -= copylen;
> src += copylen;
>
> - if (bounce_sgl[j].length == PAGE_SIZE) {
> + if (cur_dest_sgl->length == PAGE_SIZE) {
> /* full..move to next entry */
> - sg_kunmap_atomic(bounce_addr);
> + kunmap_atomic((void *)bounce_addr);
> bounce_addr = 0;
> j++;
> }
>
> /* if we need to use another bounce buffer */
> - if (srclen && bounce_addr == 0)
> - bounce_addr = sg_kmap_atomic(bounce_sgl,
> j);
> + if (srclen && bounce_addr == 0) {
> + cur_dest_sgl = sg_next(cur_dest_sgl);
> + bounce_addr = (unsigned long)
> + kmap_atomic(
> + sg_page(cur_dest_sgl));
> + }
>
> }
>
> - sg_kunmap_atomic(src_addr - orig_sgl[i].offset);
> + kunmap_atomic((void *)(src_addr - cur_src_sgl->offset));
> + cur_src_sgl = sg_next(cur_src_sgl);
> }
>
> if (bounce_addr)
> - sg_kunmap_atomic(bounce_addr);
> + kunmap_atomic((void *)bounce_addr);
>
> local_irq_restore(flags);
>
> @@ -1536,6 +1549,7 @@ static int storvsc_queuecommand(struct Scsi_Host
> *host, struct scsi_cmnd *scmnd)
> struct scatterlist *sgl;
> unsigned int sg_count = 0;
> struct vmscsi_request *vm_srb;
> + struct scatterlist *cur_sgl;
>
> if (vmstor_current_major <= VMSTOR_WIN8_MAJOR) {
> /*
> @@ -1617,10 +1631,12 @@ static int storvsc_queuecommand(struct
> Scsi_Host *host, struct scsi_cmnd *scmnd)
> }
>
> cmd_request->data_buffer.offset = sgl[0].offset;
> -
> - for (i = 0; i < sg_count; i++)
> + cur_sgl = sgl;
> + for (i = 0; i < sg_count; i++) {
> cmd_request->data_buffer.pfn_array[i] =
> - page_to_pfn(sg_page((&sgl[i])));
> + page_to_pfn(sg_page((cur_sgl)));
> + cur_sgl = sg_next(cur_sgl);
> + }
>
> } else if (scsi_sglist(scmnd)) {
> cmd_request->data_buffer.offset =
> --
> 1.7.4.1
>
> _______________________________________________
> devel mailing list
> devel@...uxdriverproject.org
> http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
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