netdev - [PATCH RFC 29/35] scsi: core: drop nth

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Message-ID: <20250821200701.1329277-30-david@redhat.com>
Date: Thu, 21 Aug 2025 22:06:55 +0200
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: David Hildenbrand <david@...hat.com>,
	"James E.J. Bottomley" <James.Bottomley@...senPartnership.com>,
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	Zi Yan <ziy@...dia.com>
Subject: [PATCH RFC 29/35] scsi: core: drop nth_page() usage within SG entry

It's no longer required to use nth_page() when iterating pages within a
single SG entry, so let's drop the nth_page() usage.

Cc: "James E.J. Bottomley" <James.Bottomley@...senPartnership.com>
Cc: "Martin K. Petersen" <martin.petersen@...cle.com>
Cc: Doug Gilbert <dgilbert@...erlog.com>
Signed-off-by: David Hildenbrand <david@...hat.com>
---
 drivers/scsi/scsi_lib.c | 3 +--
 drivers/scsi/sg.c       | 3 +--
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 0c65ecfedfbd6..f523f85828b89 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -3148,8 +3148,7 @@ void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
 	/* Offset starting from the beginning of first page in this sg-entry */
 	*offset = *offset - len_complete + sg->offset;
 
-	/* Assumption: contiguous pages can be accessed as "page + i" */
-	page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
+	page = sg_page(sg) + *offset / PAGE_SIZE;
 	*offset &= ~PAGE_MASK;
 
 	/* Bytes in this sg-entry from *offset to the end of the page */
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 3c02a5f7b5f39..2c653f2b21133 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -1235,8 +1235,7 @@ sg_vma_fault(struct vm_fault *vmf)
 		len = vma->vm_end - sa;
 		len = (len < length) ? len : length;
 		if (offset < len) {
-			struct page *page = nth_page(rsv_schp->pages[k],
-						     offset >> PAGE_SHIFT);
+			struct page *page = rsv_schp->pages[k] + offset / PAGE_SIZE;
 			get_page(page);	/* increment page count */
 			vmf->page = page;
 			return 0; /* success */
-- 
2.50.1