On Wed, 2021-03-24 at 09:52 -0700, Joe Perches wrote:
On Wed, 2021-03-24 at 17:42 +0100, Arnd Bergmann wrote:
On Wed, Mar 24, 2021 at 3:20 PM Joe Perches joe@perches.com wrote:
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diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
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@@ -197,6 +197,12 @@ static void imx_ldb_encoder_enable(struct drm_encoder *encoder) int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN; int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder);
if (mux < 0 || mux >= ARRAY_SIZE(ldb->clk_sel)) {dev_warn(ldb->dev, "%s: invalid mux %d\n",__func__, ERR_PTR(mux));This does not compile without warnings.
drivers/gpu/drm/imx/imx-ldb.c: In function ‘imx_ldb_encoder_enable’: drivers/gpu/drm/imx/imx-ldb.c:201:22: warning: format ‘%d’ expects argument of type ‘int’, but argument 4 has type ‘void *’ [-Wformat=] 201 | dev_warn(ldb->dev, "%s: invalid mux %d\n", | ^~~~~~~~~~~~~~~~~~~~~~
If you want to use ERR_PTR, the %d should be %pe as ERR_PTR is converting an int a void * to decode the error type and emit it as a string.
Sorry about that.
I decided against using ERR_PTR() in order to also check for positive array overflow, but the version I tested was different from the version I sent.
v3 coming.
Thanks. No worries.
Up to you, vsprintf would emit the positive mux as a funky hashed hex value by default if you use ERR_PTR with mux > ARRAY_SIZE so perhaps %d without the ERR_PTR use makes the most sense.
Maybe it's better to output non PTR_ERR %pe uses as decimal so this sort of code would work. --- lib/vsprintf.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 3600db686fa4..debdd1c62038 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -619,19 +619,23 @@ static char *string_nocheck(char *buf, char *end, const char *s, return widen_string(buf, len, end, spec); }
-static char *err_ptr(char *buf, char *end, void *ptr, - struct printf_spec spec) +static noinline_for_stack +char *err_ptr(char *buf, char *end, void *ptr, struct printf_spec spec) { int err = PTR_ERR(ptr); - const char *sym = errname(err);
- if (sym) - return string_nocheck(buf, end, sym, spec); + if (IS_ERR(ptr)) { + const char *sym = errname(err); + + if (sym) + return string_nocheck(buf, end, sym, spec); + }
/* - * Somebody passed ERR_PTR(-1234) or some other non-existing - * Efoo - or perhaps CONFIG_SYMBOLIC_ERRNAME=n. Fall back to - * printing it as its decimal representation. + * Somebody passed ERR_PTR(-1234) or some other non-existing -E<FOO> + * or perhaps CONFIG_SYMBOLIC_ERRNAME=n + * or perhaps a positive number like an array index + * Fall back to printing it as its decimal representation. */ spec.flags |= SIGN; spec.base = 10; @@ -2407,9 +2411,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, case 'x': return pointer_string(buf, end, ptr, spec); case 'e': - /* %pe with a non-ERR_PTR gets treated as plain %p */ - if (!IS_ERR(ptr)) - break; + /* %pe with a non-ERR_PTR(ptr) gets treated as %ld */ return err_ptr(buf, end, ptr, spec); case 'u': case 'k':
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