mtd: rawnand: Ensure all continuous terms are always in sync

[ Upstream commit 6fb075f ]

While crossing a LUN boundary, it is probably safer (and clearer) to
keep all members of the continuous read structure aligned, including the
pause page (which is the last page of the lun or the last page of the
continuous read). Once these members properly in sync, we can use the
rawnand_cap_cont_reads() helper everywhere to "prepare" the next
continuous read if there is one.

Fixes: bbcd80f ("mtd: rawnand: Prevent crossing LUN boundaries during sequential reads")
Cc: stable@vger.kernel.org
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20240223115545.354541-4-miquel.raynal@bootlin.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/mtd/nand/raw/nand_base.c

@@ -1232,6 +1232,15 @@ static void rawnand_cap_cont_reads(struct nand_chip *chip)
 		chip->cont_read.pause_page = rawnand_last_page_of_lun(ppl, first_lun);
 	else
 		chip->cont_read.pause_page = chip->cont_read.last_page;
+
+	if (chip->cont_read.first_page == chip->cont_read.pause_page) {
+		chip->cont_read.first_page++;
+		chip->cont_read.pause_page = min(chip->cont_read.last_page,
+						 rawnand_last_page_of_lun(ppl, first_lun + 1));
+	}
+
+	if (chip->cont_read.first_page >= chip->cont_read.last_page)
+		chip->cont_read.ongoing = false;
 }
 
 static int nand_lp_exec_cont_read_page_op(struct nand_chip *chip, unsigned int page,
@@ -1298,12 +1307,11 @@ static int nand_lp_exec_cont_read_page_op(struct nand_chip *chip, unsigned int p
 	if (!chip->cont_read.ongoing)
 		return 0;
 
-	if (page == chip->cont_read.pause_page &&
-	    page != chip->cont_read.last_page) {
-		chip->cont_read.first_page = chip->cont_read.pause_page + 1;
-		rawnand_cap_cont_reads(chip);
-	} else if (page == chip->cont_read.last_page) {
+	if (page == chip->cont_read.last_page) {
 		chip->cont_read.ongoing = false;
+	} else if (page == chip->cont_read.pause_page) {
+		chip->cont_read.first_page++;
+		rawnand_cap_cont_reads(chip);
 	}
 
 	return 0;
@@ -3510,10 +3518,7 @@ static void rawnand_cont_read_skip_first_page(struct nand_chip *chip, unsigned i
 		return;
 
 	chip->cont_read.first_page++;
-	if (chip->cont_read.first_page == chip->cont_read.pause_page)
-		chip->cont_read.first_page++;
-	if (chip->cont_read.first_page >= chip->cont_read.last_page)
-		chip->cont_read.ongoing = false;
+	rawnand_cap_cont_reads(chip);
 }
 
 /**