[PATCH v2 1/1] mtd: cfi_cmdset_0001: Factor out do_write_buffer_locked() to reduce stack frame

[PATCH v2 1/1] mtd: cfi_cmdset_0001: Factor out do_write_buffer_locked() to reduce stack frame

[Andy Shevchenko]

Compiler is not happy about used stack frame:

drivers/mtd/chips/cfi_cmdset_0001.c: In function 'do_write_buffer':
drivers/mtd/chips/cfi_cmdset_0001.c:1887:1: error: the frame size of 1296 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]

Fix this by factoring out do_write_buffer_locked().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
v2: left ENABLE_VPP() and XIP_INVAL_CACHED_RANGE() where they were originally

 drivers/mtd/chips/cfi_cmdset_0001.c | 82 +++++++++++++++++------------
 1 file changed, 48 insertions(+), 34 deletions(-)

diff --git a/drivers/mtd/chips/cfi_cmdset_0001.c b/drivers/mtd/chips/cfi_cmdset_0001.c
index c10693ba265b..c495bee04053 100644
--- a/drivers/mtd/chips/cfi_cmdset_0001.c
+++ b/drivers/mtd/chips/cfi_cmdset_0001.c
@@ -1720,42 +1720,24 @@ static int cfi_intelext_write_words (struct mtd_info *mtd, loff_t to , size_t le
 }
 
 
-static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
-				    unsigned long adr, const struct kvec **pvec,
-				    unsigned long *pvec_seek, int len)
+static int __xipram do_write_buffer_locked(struct map_info *map, struct flchip *chip,
+					   unsigned long cmd_adr, unsigned long adr,
+					   const struct kvec **pvec,
+					   unsigned long *pvec_seek, int len)
 {
 	struct cfi_private *cfi = map->fldrv_priv;
 	map_word status, write_cmd, datum;
-	unsigned long cmd_adr;
-	int ret, wbufsize, word_gap, words;
+	int ret, word_gap, words;
 	const struct kvec *vec;
 	unsigned long vec_seek;
 	unsigned long initial_adr;
 	int initial_len = len;
 
-	wbufsize = cfi_interleave(cfi) << cfi->cfiq->MaxBufWriteSize;
-	adr += chip->start;
 	initial_adr = adr;
-	cmd_adr = adr & ~(wbufsize-1);
-
-	/* Sharp LH28F640BF chips need the first address for the
-	 * Page Buffer Program command. See Table 5 of
-	 * LH28F320BF, LH28F640BF, LH28F128BF Series (Appendix FUM00701) */
-	if (is_LH28F640BF(cfi))
-		cmd_adr = adr;
 
 	/* Let's determine this according to the interleave only once */
 	write_cmd = (cfi->cfiq->P_ID != P_ID_INTEL_PERFORMANCE) ? CMD(0xe8) : CMD(0xe9);
 
-	mutex_lock(&chip->mutex);
-	ret = get_chip(map, chip, cmd_adr, FL_WRITING);
-	if (ret) {
-		mutex_unlock(&chip->mutex);
-		return ret;
-	}
-
-	XIP_INVAL_CACHED_RANGE(map, initial_adr, initial_len);
-	ENABLE_VPP(map);
 	xip_disable(map, chip, cmd_adr);
 
 	/* §4.8 of the 28FxxxJ3A datasheet says "Any time SR.4 and/or SR.5 is set
@@ -1789,7 +1771,7 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
 		xip_enable(map, chip, cmd_adr);
 		printk(KERN_ERR "%s: Chip not ready for buffer write. Xstatus = %lx, status = %lx\n",
 				map->name, Xstatus.x[0], status.x[0]);
-		goto out;
+		return ret;
 	}
 
 	/* Figure out the number of words to write */
@@ -1853,7 +1835,7 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
 		chip->state = FL_STATUS;
 		xip_enable(map, chip, cmd_adr);
 		printk(KERN_ERR "%s: buffer write error (status timeout)\n", map->name);
-		goto out;
+		return ret;
 	}
 
 	/* check for errors */
@@ -1866,21 +1848,53 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
 		map_write(map, CMD(0x70), cmd_adr);
 		xip_enable(map, chip, cmd_adr);
 
-		if (chipstatus & 0x02) {
-			ret = -EROFS;
-		} else if (chipstatus & 0x08) {
+		if (chipstatus & 0x02)
+			return -EROFS;
+
+		if (chipstatus & 0x08) {
 			printk(KERN_ERR "%s: buffer write error (bad VPP)\n", map->name);
-			ret = -EIO;
-		} else {
-			printk(KERN_ERR "%s: buffer write error (status 0x%lx)\n", map->name, chipstatus);
-			ret = -EINVAL;
+			return  -EIO;
 		}
 
-		goto out;
+		printk(KERN_ERR "%s: buffer write error (status 0x%lx)\n", map->name, chipstatus);
+		return -EINVAL;
 	}
 
 	xip_enable(map, chip, cmd_adr);
- out:	DISABLE_VPP(map);
+	return 0;
+}
+
+static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
+				    unsigned long adr, const struct kvec **pvec,
+				    unsigned long *pvec_seek, int len)
+{
+	struct cfi_private *cfi = map->fldrv_priv;
+	unsigned long cmd_adr;
+	int ret, wbufsize;
+
+	wbufsize = cfi_interleave(cfi) << cfi->cfiq->MaxBufWriteSize;
+	adr += chip->start;
+	cmd_adr = adr & ~(wbufsize - 1);
+
+	/* Sharp LH28F640BF chips need the first address for the
+	 * Page Buffer Program command. See Table 5 of
+	 * LH28F320BF, LH28F640BF, LH28F128BF Series (Appendix FUM00701) */
+	if (is_LH28F640BF(cfi))
+		cmd_adr = adr;
+
+	mutex_lock(&chip->mutex);
+	ret = get_chip(map, chip, cmd_adr, FL_WRITING);
+	if (ret) {
+		mutex_unlock(&chip->mutex);
+		return ret;
+	}
+
+	XIP_INVAL_CACHED_RANGE(map, adr, len);
+	ENABLE_VPP(map);
+
+	ret = do_write_buffer_locked(map, chip, cmd_adr, adr, pvec, pvec_seek, len);
+
+	DISABLE_VPP(map);
 	put_chip(map, chip, cmd_adr);
 	mutex_unlock(&chip->mutex);
 	return ret;
-- 
2.50.1

Re: [PATCH v2 1/1] mtd: cfi_cmdset_0001: Factor out do_write_buffer_locked() to reduce stack frame

[kernel test robot]

Hi Andy,

kernel test robot noticed the following build warnings:

[auto build test WARNING on mtd/mtd/next]
[also build test WARNING on mtd/mtd/fixes linus/master v6.19-rc6 next-20260123]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Andy-Shevchenko/mtd-cfi_cmdset_0001-Factor-out-do_write_buffer_locked-to-reduce-stack-frame/20260124-213936
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next
patch link:    https://lore.kernel.org/r/20260124133730.3454241-1-andriy.shevchenko%40linux.intel.com
patch subject: [PATCH v2 1/1] mtd: cfi_cmdset_0001: Factor out do_write_buffer_locked() to reduce stack frame
config: xtensa-randconfig-002-20260125 (https://download.01.org/0day-ci/archive/20260125/202601250653.LXBUL5W6-lkp@intel.com/config)
compiler: xtensa-linux-gcc (GCC) 8.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260125/202601250653.LXBUL5W6-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202601250653.LXBUL5W6-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/mtd/chips/cfi_cmdset_0001.c: In function 'do_write_buffer_locked':
>> drivers/mtd/chips/cfi_cmdset_0001.c:1734:6: warning: unused variable 'initial_len' [-Wunused-variable]
     int initial_len = len;
         ^~~~~~~~~~~
>> drivers/mtd/chips/cfi_cmdset_0001.c:1733:16: warning: variable 'initial_adr' set but not used [-Wunused-but-set-variable]
     unsigned long initial_adr;
                   ^~~~~~~~~~~


vim +/initial_len +1734 drivers/mtd/chips/cfi_cmdset_0001.c

^1da177e4c3f415 Linus Torvalds   2005-04-16  1721  
^1da177e4c3f415 Linus Torvalds   2005-04-16  1722  
b8a0764c058e872 Andy Shevchenko  2026-01-24  1723  static int __xipram do_write_buffer_locked(struct map_info *map, struct flchip *chip,
b8a0764c058e872 Andy Shevchenko  2026-01-24  1724  					   unsigned long cmd_adr, unsigned long adr,
b8a0764c058e872 Andy Shevchenko  2026-01-24  1725  					   const struct kvec **pvec,
e102d54abf6806b Nicolas Pitre    2005-08-06  1726  					   unsigned long *pvec_seek, int len)
^1da177e4c3f415 Linus Torvalds   2005-04-16  1727  {
^1da177e4c3f415 Linus Torvalds   2005-04-16  1728  	struct cfi_private *cfi = map->fldrv_priv;
c172471b78255a5 Nicolas Pitre    2006-03-30  1729  	map_word status, write_cmd, datum;
b8a0764c058e872 Andy Shevchenko  2026-01-24  1730  	int ret, word_gap, words;
e102d54abf6806b Nicolas Pitre    2005-08-06  1731  	const struct kvec *vec;
e102d54abf6806b Nicolas Pitre    2005-08-06  1732  	unsigned long vec_seek;
646fd12784d5061 Massimo Cirillo  2008-01-11 @1733  	unsigned long initial_adr;
646fd12784d5061 Massimo Cirillo  2008-01-11 @1734  	int initial_len = len;
^1da177e4c3f415 Linus Torvalds   2005-04-16  1735  
646fd12784d5061 Massimo Cirillo  2008-01-11  1736  	initial_adr = adr;
812c5fa82bae9f3 Andrea Adami     2014-06-02  1737  
^1da177e4c3f415 Linus Torvalds   2005-04-16  1738  	/* Let's determine this according to the interleave only once */
b5d194ceaeffce6 Guillaume LECERF 2010-10-26  1739  	write_cmd = (cfi->cfiq->P_ID != P_ID_INTEL_PERFORMANCE) ? CMD(0xe8) : CMD(0xe9);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1740  
^1da177e4c3f415 Linus Torvalds   2005-04-16  1741  	xip_disable(map, chip, cmd_adr);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1742  
151e76590f66f54 David Woodhouse  2006-05-14  1743  	/* §4.8 of the 28FxxxJ3A datasheet says "Any time SR.4 and/or SR.5 is set
^1da177e4c3f415 Linus Torvalds   2005-04-16  1744  	   [...], the device will not accept any more Write to Buffer commands".
^1da177e4c3f415 Linus Torvalds   2005-04-16  1745  	   So we must check here and reset those bits if they're set. Otherwise
^1da177e4c3f415 Linus Torvalds   2005-04-16  1746  	   we're just pissing in the wind */
6e7a6809c555aeb Nicolas Pitre    2006-03-29  1747  	if (chip->state != FL_STATUS) {
^1da177e4c3f415 Linus Torvalds   2005-04-16  1748  		map_write(map, CMD(0x70), cmd_adr);
6e7a6809c555aeb Nicolas Pitre    2006-03-29  1749  		chip->state = FL_STATUS;
6e7a6809c555aeb Nicolas Pitre    2006-03-29  1750  	}
^1da177e4c3f415 Linus Torvalds   2005-04-16  1751  	status = map_read(map, cmd_adr);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1752  	if (map_word_bitsset(map, status, CMD(0x30))) {
^1da177e4c3f415 Linus Torvalds   2005-04-16  1753  		xip_enable(map, chip, cmd_adr);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1754  		printk(KERN_WARNING "SR.4 or SR.5 bits set in buffer write (status %lx). Clearing.\n", status.x[0]);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1755  		xip_disable(map, chip, cmd_adr);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1756  		map_write(map, CMD(0x50), cmd_adr);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1757  		map_write(map, CMD(0x70), cmd_adr);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1758  	}
^1da177e4c3f415 Linus Torvalds   2005-04-16  1759  
^1da177e4c3f415 Linus Torvalds   2005-04-16  1760  	chip->state = FL_WRITING_TO_BUFFER;
638d983840bb64e Nicolas Pitre    2005-08-06  1761  	map_write(map, write_cmd, cmd_adr);
e93cafe45fd7493 Anders Grafström 2008-08-05  1762  	ret = WAIT_TIMEOUT(map, chip, cmd_adr, 0, 0);
c172471b78255a5 Nicolas Pitre    2006-03-30  1763  	if (ret) {
^1da177e4c3f415 Linus Torvalds   2005-04-16  1764  		/* Argh. Not ready for write to buffer */
c172471b78255a5 Nicolas Pitre    2006-03-30  1765  		map_word Xstatus = map_read(map, cmd_adr);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1766  		map_write(map, CMD(0x70), cmd_adr);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1767  		chip->state = FL_STATUS;
c172471b78255a5 Nicolas Pitre    2006-03-30  1768  		status = map_read(map, cmd_adr);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1769  		map_write(map, CMD(0x50), cmd_adr);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1770  		map_write(map, CMD(0x70), cmd_adr);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1771  		xip_enable(map, chip, cmd_adr);
c172471b78255a5 Nicolas Pitre    2006-03-30  1772  		printk(KERN_ERR "%s: Chip not ready for buffer write. Xstatus = %lx, status = %lx\n",
c172471b78255a5 Nicolas Pitre    2006-03-30  1773  				map->name, Xstatus.x[0], status.x[0]);
b8a0764c058e872 Andy Shevchenko  2026-01-24  1774  		return ret;
^1da177e4c3f415 Linus Torvalds   2005-04-16  1775  	}
^1da177e4c3f415 Linus Torvalds   2005-04-16  1776  
e102d54abf6806b Nicolas Pitre    2005-08-06  1777  	/* Figure out the number of words to write */
e102d54abf6806b Nicolas Pitre    2005-08-06  1778  	word_gap = (-adr & (map_bankwidth(map)-1));
c8872b069c53697 Julia Lawall     2008-08-02  1779  	words = DIV_ROUND_UP(len - word_gap, map_bankwidth(map));
e102d54abf6806b Nicolas Pitre    2005-08-06  1780  	if (!word_gap) {
e102d54abf6806b Nicolas Pitre    2005-08-06  1781  		words--;
e102d54abf6806b Nicolas Pitre    2005-08-06  1782  	} else {
e102d54abf6806b Nicolas Pitre    2005-08-06  1783  		word_gap = map_bankwidth(map) - word_gap;
e102d54abf6806b Nicolas Pitre    2005-08-06  1784  		adr -= word_gap;
e102d54abf6806b Nicolas Pitre    2005-08-06  1785  		datum = map_word_ff(map);
e102d54abf6806b Nicolas Pitre    2005-08-06  1786  	}
e102d54abf6806b Nicolas Pitre    2005-08-06  1787  
^1da177e4c3f415 Linus Torvalds   2005-04-16  1788  	/* Write length of data to come */
e102d54abf6806b Nicolas Pitre    2005-08-06  1789  	map_write(map, CMD(words), cmd_adr );
^1da177e4c3f415 Linus Torvalds   2005-04-16  1790  
^1da177e4c3f415 Linus Torvalds   2005-04-16  1791  	/* Write data */
e102d54abf6806b Nicolas Pitre    2005-08-06  1792  	vec = *pvec;
e102d54abf6806b Nicolas Pitre    2005-08-06  1793  	vec_seek = *pvec_seek;
e102d54abf6806b Nicolas Pitre    2005-08-06  1794  	do {
e102d54abf6806b Nicolas Pitre    2005-08-06  1795  		int n = map_bankwidth(map) - word_gap;
e102d54abf6806b Nicolas Pitre    2005-08-06  1796  		if (n > vec->iov_len - vec_seek)
e102d54abf6806b Nicolas Pitre    2005-08-06  1797  			n = vec->iov_len - vec_seek;
e102d54abf6806b Nicolas Pitre    2005-08-06  1798  		if (n > len)
e102d54abf6806b Nicolas Pitre    2005-08-06  1799  			n = len;
^1da177e4c3f415 Linus Torvalds   2005-04-16  1800  
e102d54abf6806b Nicolas Pitre    2005-08-06  1801  		if (!word_gap && len < map_bankwidth(map))
e102d54abf6806b Nicolas Pitre    2005-08-06  1802  			datum = map_word_ff(map);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1803  
e102d54abf6806b Nicolas Pitre    2005-08-06  1804  		datum = map_word_load_partial(map, datum,
e102d54abf6806b Nicolas Pitre    2005-08-06  1805  					      vec->iov_base + vec_seek,
e102d54abf6806b Nicolas Pitre    2005-08-06  1806  					      word_gap, n);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1807  
e102d54abf6806b Nicolas Pitre    2005-08-06  1808  		len -= n;
e102d54abf6806b Nicolas Pitre    2005-08-06  1809  		word_gap += n;
e102d54abf6806b Nicolas Pitre    2005-08-06  1810  		if (!len || word_gap == map_bankwidth(map)) {
e102d54abf6806b Nicolas Pitre    2005-08-06  1811  			map_write(map, datum, adr);
e102d54abf6806b Nicolas Pitre    2005-08-06  1812  			adr += map_bankwidth(map);
e102d54abf6806b Nicolas Pitre    2005-08-06  1813  			word_gap = 0;
e102d54abf6806b Nicolas Pitre    2005-08-06  1814  		}
e102d54abf6806b Nicolas Pitre    2005-08-06  1815  
e102d54abf6806b Nicolas Pitre    2005-08-06  1816  		vec_seek += n;
e102d54abf6806b Nicolas Pitre    2005-08-06  1817  		if (vec_seek == vec->iov_len) {
e102d54abf6806b Nicolas Pitre    2005-08-06  1818  			vec++;
e102d54abf6806b Nicolas Pitre    2005-08-06  1819  			vec_seek = 0;
^1da177e4c3f415 Linus Torvalds   2005-04-16  1820  		}
e102d54abf6806b Nicolas Pitre    2005-08-06  1821  	} while (len);
e102d54abf6806b Nicolas Pitre    2005-08-06  1822  	*pvec = vec;
e102d54abf6806b Nicolas Pitre    2005-08-06  1823  	*pvec_seek = vec_seek;
^1da177e4c3f415 Linus Torvalds   2005-04-16  1824  
^1da177e4c3f415 Linus Torvalds   2005-04-16  1825  	/* GO GO GO */
^1da177e4c3f415 Linus Torvalds   2005-04-16  1826  	map_write(map, CMD(0xd0), cmd_adr);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1827  	chip->state = FL_WRITING;
^1da177e4c3f415 Linus Torvalds   2005-04-16  1828  
c172471b78255a5 Nicolas Pitre    2006-03-30  1829  	ret = INVAL_CACHE_AND_WAIT(map, chip, cmd_adr,
646fd12784d5061 Massimo Cirillo  2008-01-11  1830  				   initial_adr, initial_len,
e93cafe45fd7493 Anders Grafström 2008-08-05  1831  				   chip->buffer_write_time,
e93cafe45fd7493 Anders Grafström 2008-08-05  1832  				   chip->buffer_write_time_max);
c172471b78255a5 Nicolas Pitre    2006-03-30  1833  	if (ret) {
4843653cab0db03 Nicolas Pitre    2005-08-06  1834  		map_write(map, CMD(0x70), cmd_adr);
^1da177e4c3f415 Linus Torvalds   2005-04-16  1835  		chip->state = FL_STATUS;
^1da177e4c3f415 Linus Torvalds   2005-04-16  1836  		xip_enable(map, chip, cmd_adr);
4843653cab0db03 Nicolas Pitre    2005-08-06  1837  		printk(KERN_ERR "%s: buffer write error (status timeout)\n", map->name);
b8a0764c058e872 Andy Shevchenko  2026-01-24  1838  		return ret;
^1da177e4c3f415 Linus Torvalds   2005-04-16  1839  	}
^1da177e4c3f415 Linus Torvalds   2005-04-16  1840  
4843653cab0db03 Nicolas Pitre    2005-08-06  1841  	/* check for errors */
c172471b78255a5 Nicolas Pitre    2006-03-30  1842  	status = map_read(map, cmd_adr);
4843653cab0db03 Nicolas Pitre    2005-08-06  1843  	if (map_word_bitsset(map, status, CMD(0x1a))) {
4843653cab0db03 Nicolas Pitre    2005-08-06  1844  		unsigned long chipstatus = MERGESTATUS(status);
4843653cab0db03 Nicolas Pitre    2005-08-06  1845  
4843653cab0db03 Nicolas Pitre    2005-08-06  1846  		/* reset status */
^1da177e4c3f415 Linus Torvalds   2005-04-16  1847  		map_write(map, CMD(0x50), cmd_adr);
4843653cab0db03 Nicolas Pitre    2005-08-06  1848  		map_write(map, CMD(0x70), cmd_adr);
4843653cab0db03 Nicolas Pitre    2005-08-06  1849  		xip_enable(map, chip, cmd_adr);
4843653cab0db03 Nicolas Pitre    2005-08-06  1850  
b8a0764c058e872 Andy Shevchenko  2026-01-24  1851  		if (chipstatus & 0x02)
b8a0764c058e872 Andy Shevchenko  2026-01-24  1852  			return -EROFS;
b8a0764c058e872 Andy Shevchenko  2026-01-24  1853  
b8a0764c058e872 Andy Shevchenko  2026-01-24  1854  		if (chipstatus & 0x08) {
4843653cab0db03 Nicolas Pitre    2005-08-06  1855  			printk(KERN_ERR "%s: buffer write error (bad VPP)\n", map->name);
b8a0764c058e872 Andy Shevchenko  2026-01-24  1856  			return  -EIO;
4843653cab0db03 Nicolas Pitre    2005-08-06  1857  		}
4843653cab0db03 Nicolas Pitre    2005-08-06  1858  
b8a0764c058e872 Andy Shevchenko  2026-01-24  1859  		printk(KERN_ERR "%s: buffer write error (status 0x%lx)\n", map->name, chipstatus);
b8a0764c058e872 Andy Shevchenko  2026-01-24  1860  		return -EINVAL;
^1da177e4c3f415 Linus Torvalds   2005-04-16  1861  	}
^1da177e4c3f415 Linus Torvalds   2005-04-16  1862  
^1da177e4c3f415 Linus Torvalds   2005-04-16  1863  	xip_enable(map, chip, cmd_adr);
b8a0764c058e872 Andy Shevchenko  2026-01-24  1864  	return 0;
b8a0764c058e872 Andy Shevchenko  2026-01-24  1865  }
b8a0764c058e872 Andy Shevchenko  2026-01-24  1866  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

[PATCH v2 1/1] mtd: cfi_cmdset_0001: Factor out do_write_buffer_locked() to reduce stack frame

[Andy Shevchenko]

Compiler is not happy about used stack frame:

drivers/mtd/chips/cfi_cmdset_0001.c: In function 'do_write_buffer':
drivers/mtd/chips/cfi_cmdset_0001.c:1887:1: error: the frame size of 1296 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]

Fix this by factoring out do_write_buffer_locked().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
v2: kept DIS/ENABLE_VPP paired
 drivers/mtd/chips/cfi_cmdset_0001.c | 82 +++++++++++++++++------------
 1 file changed, 48 insertions(+), 34 deletions(-)

diff --git a/drivers/mtd/chips/cfi_cmdset_0001.c b/drivers/mtd/chips/cfi_cmdset_0001.c
index c10693ba265b..c495bee04053 100644
--- a/drivers/mtd/chips/cfi_cmdset_0001.c
+++ b/drivers/mtd/chips/cfi_cmdset_0001.c
@@ -1720,42 +1720,24 @@ static int cfi_intelext_write_words (struct mtd_info *mtd, loff_t to , size_t le
 }
 
 
-static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
-				    unsigned long adr, const struct kvec **pvec,
-				    unsigned long *pvec_seek, int len)
+static int __xipram do_write_buffer_locked(struct map_info *map, struct flchip *chip,
+					   unsigned long cmd_adr, unsigned long adr,
+					   const struct kvec **pvec,
+					   unsigned long *pvec_seek, int len)
 {
 	struct cfi_private *cfi = map->fldrv_priv;
 	map_word status, write_cmd, datum;
-	unsigned long cmd_adr;
-	int ret, wbufsize, word_gap, words;
+	int ret, word_gap, words;
 	const struct kvec *vec;
 	unsigned long vec_seek;
 	unsigned long initial_adr;
 	int initial_len = len;
 
-	wbufsize = cfi_interleave(cfi) << cfi->cfiq->MaxBufWriteSize;
-	adr += chip->start;
 	initial_adr = adr;
-	cmd_adr = adr & ~(wbufsize-1);
-
-	/* Sharp LH28F640BF chips need the first address for the
-	 * Page Buffer Program command. See Table 5 of
-	 * LH28F320BF, LH28F640BF, LH28F128BF Series (Appendix FUM00701) */
-	if (is_LH28F640BF(cfi))
-		cmd_adr = adr;
 
 	/* Let's determine this according to the interleave only once */
 	Mwrite_cmd = (cfi->cfiq->P_ID != P_ID_INTEL_PERFORMANCE) ? CMD(0xe8) : CMD(0xe9);
 
-	mutex_lock(&chip->mutex);
-	ret = get_chip(map, chip, cmd_adr, FL_WRITING);
-	if (ret) {
-		mutex_unlock(&chip->mutex);
-		return ret;
-	}
-
-	XIP_INVAL_CACHED_RANGE(map, initial_adr, initial_len);
-	ENABLE_VPP(map);
 	xip_disable(map, chip, cmd_adr);
 
 	/* §4.8 of the 28FxxxJ3A datasheet says "Any time SR.4 and/or SR.5 is set
@@ -1789,7 +1771,7 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
 		xip_enable(map, chip, cmd_adr);
 		printk(KERN_ERR "%s: Chip not ready for buffer write. Xstatus = %lx, status = %lx\n",
 				map->name, Xstatus.x[0], status.x[0]);
-		goto out;
+		return ret;
 	}
 
 	/* Figure out the number of words to write */
@@ -1853,7 +1835,7 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
 		chip->state = FL_STATUS;
 		xip_enable(map, chip, cmd_adr);
 		printk(KERN_ERR "%s: buffer write error (status timeout)\n", map->name);
-		goto out;
+		return ret;
 	}
 
 	/* check for errors */
@@ -1866,21 +1848,53 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
 		map_write(map, CMD(0x70), cmd_adr);
 		xip_enable(map, chip, cmd_adr);
 
-		if (chipstatus & 0x02) {
-			ret = -EROFS;
-		} else if (chipstatus & 0x08) {
+		if (chipstatus & 0x02)
+			return -EROFS;
+
+		if (chipstatus & 0x08) {
 			printk(KERN_ERR "%s: buffer write error (bad VPP)\n", map->name);
-			ret = -EIO;
-		} else {
-			printk(KERN_ERR "%s: buffer write error (status 0x%lx)\n", map->name, chipstatus);
-			ret = -EINVAL;
+			return  -EIO;
 		}
 
-		goto out;
+		printk(KERN_ERR "%s: buffer write error (status 0x%lx)\n", map->name, chipstatus);
+		return -EINVAL;
 	}
 
 	xip_enable(map, chip, cmd_adr);
- out:	DISABLE_VPP(map);
+	return 0;
+}
+
+static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
+				    unsigned long adr, const struct kvec **pvec,
+				    unsigned long *pvec_seek, int len)
+{
+	struct cfi_private *cfi = map->fldrv_priv;
+	unsigned long cmd_adr;
+	int ret, wbufsize;
+
+	wbufsize = cfi_interleave(cfi) << cfi->cfiq->MaxBufWriteSize;
+	adr += chip->start;
+	cmd_adr = adr & ~(wbufsize - 1);
+
+	/* Sharp LH28F640BF chips need the first address for the
+	 * Page Buffer Program command. See Table 5 of
+	 * LH28F320BF, LH28F640BF, LH28F128BF Series (Appendix FUM00701) */
+	if (is_LH28F640BF(cfi))
+		cmd_adr = adr;
+
+	mutex_lock(&chip->mutex);
+	ret = get_chip(map, chip, cmd_adr, FL_WRITING);
+	if (ret) {
+		mutex_unlock(&chip->mutex);
+		return ret;
+	}
+
+	XIP_INVAL_CACHED_RANGE(map, adr, len);
+	ENABLE_VPP(map);
+
+	ret = do_write_buffer_locked(map, chip, cmd_adr, adr, pvec, pvec_seek, len);
+
+	DISABLE_VPP(map);
 	put_chip(map, chip, cmd_adr);
 	mutex_unlock(&chip->mutex);
 	return ret;
-- 
2.50.1

Re: [PATCH v2 1/1] mtd: cfi_cmdset_0001: Factor out do_write_buffer_locked() to reduce stack frame

[Andy Shevchenko]

On Wed, Feb 04, 2026 at 02:25:27AM +0100, Andy Shevchenko wrote:
> Compiler is not happy about used stack frame:
> 
> drivers/mtd/chips/cfi_cmdset_0001.c: In function 'do_write_buffer':
> drivers/mtd/chips/cfi_cmdset_0001.c:1887:1: error: the frame size of 1296 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]
> 
> Fix this by factoring out do_write_buffer_locked().

My gosh, I already sent a v2 earlier and there were some replies,
I need to check...

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 1/1] mtd: cfi_cmdset_0001: Factor out do_write_buffer_locked() to reduce stack frame

[Miquel Raynal]

Hi Andy,

On 04/02/2026 at 23:12:00 +02, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:

> On Wed, Feb 04, 2026 at 02:25:27AM +0100, Andy Shevchenko wrote:
>> Compiler is not happy about used stack frame:
>> 
>> drivers/mtd/chips/cfi_cmdset_0001.c: In function 'do_write_buffer':
>> drivers/mtd/chips/cfi_cmdset_0001.c:1887:1: error: the frame size of 1296 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]
>> 
>> Fix this by factoring out do_write_buffer_locked().
>
> My gosh, I already sent a v2 earlier and there were some replies,
> I need to check...

I'm not sure I get what you mean here? I got no reply (in my inbox) to
your v2. I am letting a bit of time for Vignesh to take a look, but I
know he's busy so I might take it nevertheless by the end of the week as
we are approaching the merge window.

Cheers,
Miquèl

Re: [PATCH v2 1/1] mtd: cfi_cmdset_0001: Factor out do_write_buffer_locked() to reduce stack frame

[Andy Shevchenko]

On Thu, Feb 05, 2026 at 09:51:56AM +0100, Miquel Raynal wrote:
> On 04/02/2026 at 23:12:00 +02, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> > On Wed, Feb 04, 2026 at 02:25:27AM +0100, Andy Shevchenko wrote:
> >> Compiler is not happy about used stack frame:
> >> 
> >> drivers/mtd/chips/cfi_cmdset_0001.c: In function 'do_write_buffer':
> >> drivers/mtd/chips/cfi_cmdset_0001.c:1887:1: error: the frame size of 1296 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]
> >> 
> >> Fix this by factoring out do_write_buffer_locked().
> >
> > My gosh, I already sent a v2 earlier and there were some replies,
> > I need to check...
> 
> I'm not sure I get what you mean here? I got no reply (in my inbox) to
> your v2. I am letting a bit of time for Vignesh to take a look, but I
> know he's busy so I might take it nevertheless by the end of the week as
> we are approaching the merge window.

I got some strange LKP reports, I need to check them.
Please, discard this email thread as we have it there

https://lore.kernel.org/r/20260124133730.3454241-1-andriy.shevchenko@linux.intel.com

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 1/1] mtd: cfi_cmdset_0001: Factor out do_write_buffer_locked() to reduce stack frame

[Miquel Raynal]

On 05/02/2026 at 17:57:17 +02, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:

> On Thu, Feb 05, 2026 at 09:51:56AM +0100, Miquel Raynal wrote:
>> On 04/02/2026 at 23:12:00 +02, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
>> > On Wed, Feb 04, 2026 at 02:25:27AM +0100, Andy Shevchenko wrote:
>> >> Compiler is not happy about used stack frame:
>> >> 
>> >> drivers/mtd/chips/cfi_cmdset_0001.c: In function 'do_write_buffer':
>> >> drivers/mtd/chips/cfi_cmdset_0001.c:1887:1: error: the frame size of 1296 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]
>> >> 
>> >> Fix this by factoring out do_write_buffer_locked().
>> >
>> > My gosh, I already sent a v2 earlier and there were some replies,
>> > I need to check...
>> 
>> I'm not sure I get what you mean here? I got no reply (in my inbox) to
>> your v2. I am letting a bit of time for Vignesh to take a look, but I
>> know he's busy so I might take it nevertheless by the end of the week as
>> we are approaching the merge window.
>
> I got some strange LKP reports, I need to check them.
> Please, discard this email thread as we have it there
>
> https://lore.kernel.org/r/20260124133730.3454241-1-andriy.shevchenko@linux.intel.com

Ah, this did not reach my inbox, marked SPAM... I'll discard this patch
for this cycle, feel free to resend once the report has been figured
out.

Thanks,
Miquèl

Re: [PATCH v2 1/1] mtd: cfi_cmdset_0001: Factor out do_write_buffer_locked() to reduce stack frame

[Vignesh Raghavendra]

On 05/02/26 23:04, Miquel Raynal wrote:
> On 05/02/2026 at 17:57:17 +02, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> 
>> On Thu, Feb 05, 2026 at 09:51:56AM +0100, Miquel Raynal wrote:
>>> On 04/02/2026 at 23:12:00 +02, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
>>>> On Wed, Feb 04, 2026 at 02:25:27AM +0100, Andy Shevchenko wrote:
>>>>> Compiler is not happy about used stack frame:
>>>>>
>>>>> drivers/mtd/chips/cfi_cmdset_0001.c: In function 'do_write_buffer':
>>>>> drivers/mtd/chips/cfi_cmdset_0001.c:1887:1: error: the frame size of 1296 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]
>>>>>
>>>>> Fix this by factoring out do_write_buffer_locked().
>>>>
>>>> My gosh, I already sent a v2 earlier and there were some replies,
>>>> I need to check...
>>>
>>> I'm not sure I get what you mean here? I got no reply (in my inbox) to
>>> your v2. I am letting a bit of time for Vignesh to take a look, but I
>>> know he's busy so I might take it nevertheless by the end of the week as
>>> we are approaching the merge window.
>>
>> I got some strange LKP reports, I need to check them.
>> Please, discard this email thread as we have it there
>>
>> https://lore.kernel.org/r/20260124133730.3454241-1-andriy.shevchenko@linux.intel.com
> 
> Ah, this did not reach my inbox, marked SPAM... I'll discard this patch
> for this cycle, feel free to resend once the report has been figured
> out.
> 

Yeah, things become tricky with CONFIG_MTD_XIP enabled. With
XIP_INVAL_CACHED_RANGE() moved to caller, initial_adr becomes unused
when CONFIG_MTD_XIP=y

One solution maybe to move calls to XIP_INVAL_CACHED_RANGE(),
ENABLE_VPP(map) and xip_disable() and their complementary functions to
do_write_buffer_locked() as these calls need to repeated for every
writes (if and when we find need to reuse do_write_buffer_locked())

Alternately move INVAL_CACHE_AND_WAIT() and everything after that to caller


-- 
Regards
Vignesh
https://ti.com/opensource

Re: [PATCH v2 1/1] mtd: cfi_cmdset_0001: Factor out do_write_buffer_locked() to reduce stack frame

[Andy Shevchenko]

On Fri, Feb 06, 2026 at 11:26:23AM +0530, Vignesh Raghavendra wrote:
> On 05/02/26 23:04, Miquel Raynal wrote:
> > On 05/02/2026 at 17:57:17 +02, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> >> On Thu, Feb 05, 2026 at 09:51:56AM +0100, Miquel Raynal wrote:
> >>> On 04/02/2026 at 23:12:00 +02, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> >>>> On Wed, Feb 04, 2026 at 02:25:27AM +0100, Andy Shevchenko wrote:
> >>>>> Compiler is not happy about used stack frame:
> >>>>>
> >>>>> drivers/mtd/chips/cfi_cmdset_0001.c: In function 'do_write_buffer':
> >>>>> drivers/mtd/chips/cfi_cmdset_0001.c:1887:1: error: the frame size of 1296 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]
> >>>>>
> >>>>> Fix this by factoring out do_write_buffer_locked().
> >>>>
> >>>> My gosh, I already sent a v2 earlier and there were some replies,
> >>>> I need to check...
> >>>
> >>> I'm not sure I get what you mean here? I got no reply (in my inbox) to
> >>> your v2. I am letting a bit of time for Vignesh to take a look, but I
> >>> know he's busy so I might take it nevertheless by the end of the week as
> >>> we are approaching the merge window.
> >>
> >> I got some strange LKP reports, I need to check them.
> >> Please, discard this email thread as we have it there
> >>
> >> https://lore.kernel.org/r/20260124133730.3454241-1-andriy.shevchenko@linux.intel.com
> > 
> > Ah, this did not reach my inbox, marked SPAM... I'll discard this patch
> > for this cycle, feel free to resend once the report has been figured
> > out.
> 
> Yeah, things become tricky with CONFIG_MTD_XIP enabled. With
> XIP_INVAL_CACHED_RANGE() moved to caller, initial_adr becomes unused
> when CONFIG_MTD_XIP=y
> 
> One solution maybe to move calls to XIP_INVAL_CACHED_RANGE(),
> ENABLE_VPP(map) and xip_disable() and their complementary functions to
> do_write_buffer_locked() as these calls need to repeated for every
> writes (if and when we find need to reuse do_write_buffer_locked())
> 
> Alternately move INVAL_CACHE_AND_WAIT() and everything after that to caller

Thanks for the analysis! Can you copy this as the reply to the LKP report?
I don't want to have the report and analysis in different threads, I may
forgot about this one (and actually I closed this thread for myself).

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 1/1] mtd: cfi_cmdset_0001: Factor out do_write_buffer_locked() to reduce stack frame

[Vignesh Raghavendra]

On 25/01/26 04:11, kernel test robot wrote:
> Hi Andy,
> 
> kernel test robot noticed the following build warnings:
> 
> [auto build test WARNING on mtd/mtd/next]
> [also build test WARNING on mtd/mtd/fixes linus/master v6.19-rc6 next-20260123]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Andy-Shevchenko/mtd-cfi_cmdset_0001-Factor-out-do_write_buffer_locked-to-reduce-stack-frame/20260124-213936
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next
> patch link:    https://lore.kernel.org/r/20260124133730.3454241-1-andriy.shevchenko%40linux.intel.com
> patch subject: [PATCH v2 1/1] mtd: cfi_cmdset_0001: Factor out do_write_buffer_locked() to reduce stack frame
> config: xtensa-randconfig-002-20260125 (https://download.01.org/0day-ci/archive/20260125/202601250653.LXBUL5W6-lkp@intel.com/config)
> compiler: xtensa-linux-gcc (GCC) 8.5.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260125/202601250653.LXBUL5W6-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202601250653.LXBUL5W6-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
>    drivers/mtd/chips/cfi_cmdset_0001.c: In function 'do_write_buffer_locked':
>>> drivers/mtd/chips/cfi_cmdset_0001.c:1734:6: warning: unused variable 'initial_len' [-Wunused-variable]
>      int initial_len = len;
>          ^~~~~~~~~~~
>>> drivers/mtd/chips/cfi_cmdset_0001.c:1733:16: warning: variable 'initial_adr' set but not used [-Wunused-but-set-variable]
>      unsigned long initial_adr;
>                    ^~~~~~~~~~~
> 
> 

Copying my response here again from [1] , as this LKP report seems to on a 
different thread:


Things become tricky with CONFIG_MTD_XIP enabled. With
XIP_INVAL_CACHED_RANGE() moved to caller, initial_adr becomes unused
when CONFIG_MTD_XIP=y

One solution maybe to move calls to XIP_INVAL_CACHED_RANGE(),
ENABLE_VPP(map) and xip_disable() and their complementary functions to
do_write_buffer_locked() as these calls need to repeated for every
writes (if and when we find need to reuse do_write_buffer_locked())

Alternately move INVAL_CACHE_AND_WAIT() and everything after that to 
caller


[...]

[1] https://lore.kernel.org/all/4d4ab8af-3e09-4e48-a79d-0af3453600c3@ti.com/

-- 
Regards
Vignesh
https://ti.com/opensource

Re: [PATCH v2 1/1] mtd: cfi_cmdset_0001: Factor out do_write_buffer_locked() to reduce stack frame

[Andy Shevchenko]

On Tue, Feb 10, 2026 at 03:35:39PM +0530, Vignesh Raghavendra wrote:
> On 25/01/26 04:11, kernel test robot wrote:

> > kernel test robot noticed the following build warnings:
> > 
> > [auto build test WARNING on mtd/mtd/next]
> > [also build test WARNING on mtd/mtd/fixes linus/master v6.19-rc6 next-20260123]
> > [If your patch is applied to the wrong git tree, kindly drop us a note.
> > And when submitting patch, we suggest to use '--base' as documented in
> > https://git-scm.com/docs/git-format-patch#_base_tree_information]
> > 
> > url:    https://github.com/intel-lab-lkp/linux/commits/Andy-Shevchenko/mtd-cfi_cmdset_0001-Factor-out-do_write_buffer_locked-to-reduce-stack-frame/20260124-213936
> > base:   https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next
> > patch link:    https://lore.kernel.org/r/20260124133730.3454241-1-andriy.shevchenko%40linux.intel.com
> > patch subject: [PATCH v2 1/1] mtd: cfi_cmdset_0001: Factor out do_write_buffer_locked() to reduce stack frame
> > config: xtensa-randconfig-002-20260125 (https://download.01.org/0day-ci/archive/20260125/202601250653.LXBUL5W6-lkp@intel.com/config)
> > compiler: xtensa-linux-gcc (GCC) 8.5.0
> > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260125/202601250653.LXBUL5W6-lkp@intel.com/reproduce)
> > 
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/202601250653.LXBUL5W6-lkp@intel.com/
> > 
> > All warnings (new ones prefixed by >>):
> > 
> >    drivers/mtd/chips/cfi_cmdset_0001.c: In function 'do_write_buffer_locked':
> >>> drivers/mtd/chips/cfi_cmdset_0001.c:1734:6: warning: unused variable 'initial_len' [-Wunused-variable]
> >      int initial_len = len;
> >          ^~~~~~~~~~~
> >>> drivers/mtd/chips/cfi_cmdset_0001.c:1733:16: warning: variable 'initial_adr' set but not used [-Wunused-but-set-variable]
> >      unsigned long initial_adr;
> >                    ^~~~~~~~~~~
> 
> Copying my response here again from [1] , as this LKP report seems to on a 
> different thread:

Thanks! I will look at this after -rc1 is out. Maybe earlier, but quite busy
with other issue(s).

> Things become tricky with CONFIG_MTD_XIP enabled. With
> XIP_INVAL_CACHED_RANGE() moved to caller, initial_adr becomes unused
> when CONFIG_MTD_XIP=y
> 
> One solution maybe to move calls to XIP_INVAL_CACHED_RANGE(),
> ENABLE_VPP(map) and xip_disable() and their complementary functions to
> do_write_buffer_locked() as these calls need to repeated for every
> writes (if and when we find need to reuse do_write_buffer_locked())
> 
> Alternately move INVAL_CACHE_AND_WAIT() and everything after that to 
> caller

[...]

> [1] https://lore.kernel.org/all/4d4ab8af-3e09-4e48-a79d-0af3453600c3@ti.com/

-- 
With Best Regards,
Andy Shevchenko