mtd: spi-nor: core: Add erase size check for erase command initialization

Even if erase type is same as previous region, erase size can be different
if the previous region is overlaid region. Since 'region->size' is assigned
to 'cmd->size' for overlaid region, comparing 'erase->size' and 'cmd->size'
can detect previous overlaid region.

Fixes: 5390a8df ("mtd: spi-nor: add support to non-uniform SFDP SPI NOR flash memories")
Cc: stable@vger.kernel.org
Signed-off-by: NTakahiro Kuwano <Takahiro.Kuwano@infineon.com>
[ta: Add Fixes tag and Cc to stable]
Signed-off-by: NTudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/13d47e8d8991b8a7fd8cc7b9e2a5319c56df35cc.1601612872.git.Takahiro.Kuwano@infineon.com

drivers/mtd/spi-nor/core.c

@@ -1516,6 +1516,7 @@ static int spi_nor_init_erase_cmd_list(struct spi_nor *nor,
 			goto destroy_erase_cmd_list;
 
 		if (prev_erase != erase ||
+		    erase->size != cmd->size ||
 		    region->offset & SNOR_OVERLAID_REGION) {
 			cmd = spi_nor_init_erase_cmd(region, erase);
 			if (IS_ERR(cmd)) {