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charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Last-TLS-Session-Version: TLSv1.3 Hello, On 14/04/2026 at 15:38:38 +03, Andy Shevchenko wrote: > On Thu, Apr 09, 2026 at 12:28:46PM +0100, David Laight wrote: >> On Thu, 9 Apr 2026 09:58:28 +0200 >> Lukas Wunner wrote: >> > On Thu, Apr 09, 2026 at 08:26:11AM +0100, David Laight wrote: >> > > On Wed, 8 Apr 2026 23:11:48 +0200 Andy Shevchenko wrote:=20=20 >> > > > Compiler is not happy about used stack frame: >> > > >=20 >> > > > 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=3Dframe-larger-than=3D] >> > > >=20 >> > > > Fix this by factoring out do_write_buffer_locked().=20=20 >> > >=20 >> > > Does this just split the large stack frame between two nested functi= ons? >> > > I'd also expect the compiler to inline do_write_buffer_locked() so it >> > > makes little difference. >> > > OTOH I can't immediately see where the large stack frame comes from.= =20=20 >> >=20 >> > The error occurs for an allmodconfig build on arm, which implies >> > CONFIG_KASAN_STACK=3Dy and thus increases stack usage vis-=C3=A0-vis a >> > "regular" build. >> >=20 >> > Stack usage is high here because of the three "map_word" types, >> > which can each be up to 256 unsigned longs (32 * 8), see the >> > definitions of MAX_MAP_LONGS, MAX_MAP_BANKWIDTH, map_word in >> > include/linux/mtd/map.h. >>=20 >> Ugg - that code is horrid. >> Returning structures by value isn't really a good idea. Looks like the primary reason for the stack over usage, no? Isn't playing with inline and refactoring just a tiny fix that prevents problem by just a couple of bytes? I haven't looked too carefully, but could we (Andy?) have a fix that reduces the number of map_word (as suggested, IIUC) and/or avoid passing them by value? I can also take this cleanup if enclosed in a bigger series, I don't mind because it may make the code easier to read as well, but I feel like this is not a proper fix. If it is, please explain to me again :-) Thanks, Miqu=C3=A8l