On Tue, Mar 20, 2012 at 12:46 AM, Saravana Kannan <skannan@xxxxxxxxxxxxxx> wrote: > On Tue, March 20, 2012 12:19 am, Sascha Hauer wrote: >> On Mon, Mar 19, 2012 at 08:38:25PM -0700, Saravana Kannan wrote: >>> If memory allocation for the parents array or the parent string fails, >>> then >>> fail the registration immediately instead of calling clk_register and >>> hoping it fails there. >>> >>> Return -ENOMEM on failure. >>> >>> Signed-off-by: Saravana Kannan <skannan@xxxxxxxxxxxxxx> >>> Cc: Mike Turquette <mturquette@xxxxxxxxxx> >>> Cc: Andrew Lunn <andrew@xxxxxxx> >>> Cc: Rob Herring <rob.herring@xxxxxxxxxxx> >>> Cc: Russell King <linux@xxxxxxxxxxxxxxxx> >>> Cc: Jeremy Kerr <jeremy.kerr@xxxxxxxxxxxxx> >>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> >>> Cc: Arnd Bergman <arnd.bergmann@xxxxxxxxxx> >>> Cc: Paul Walmsley <paul@xxxxxxxxx> >>> Cc: Shawn Guo <shawn.guo@xxxxxxxxxxxxx> >>> Cc: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> >>> Cc: Jamie Iles <jamie@xxxxxxxxxxxxx> >>> Cc: Richard Zhao <richard.zhao@xxxxxxxxxx> >>> Cc: Saravana Kannan <skannan@xxxxxxxxxxxxxx> >>> Cc: Magnus Damm <magnus.damm@xxxxxxxxx> >>> Cc: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx> >>> Cc: Linus Walleij <linus.walleij@xxxxxxxxxxxxxx> >>> Cc: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> >>> Cc: Amit Kucheria <amit.kucheria@xxxxxxxxxx> >>> Cc: Deepak Saxena <dsaxena@xxxxxxxxxx> >>> Cc: Grant Likely <grant.likely@xxxxxxxxxxxx> >>> --- >>> There are still some memory free issues when clk_register() fails, but I >>> will >>> fix it when I fixed the other register() fns to return ENOMEM of alloc >>> failure instead of a NULL. >>> >>> drivers/clk/clk-fixed-rate.c | 10 +++++++--- >>> 1 files changed, 7 insertions(+), 3 deletions(-) >>> >>> diff --git a/drivers/clk/clk-fixed-rate.c b/drivers/clk/clk-fixed-rate.c >>> index 90c79fb..6423ae9 100644 >>> --- a/drivers/clk/clk-fixed-rate.c >>> +++ b/drivers/clk/clk-fixed-rate.c >>> @@ -61,22 +61,26 @@ struct clk *clk_register_fixed_rate(struct device >>> *dev, const char *name, >>> parent_names = kmalloc(sizeof(char *), GFP_KERNEL); >>> >>> if (! parent_names) >>> - goto out; >>> + goto fail_ptr; >>> >>> len = sizeof(char) * strlen(parent_name); >>> >>> parent_names[0] = kmalloc(len, GFP_KERNEL); >>> >>> if (!parent_names[0]) >>> - goto out; >>> + goto fail_str; >>> >>> strncpy(parent_names[0], parent_name, len); >>> } >> >> It's easier to add a char *parent to struct clk_fixed and pass it to >> clk_register with &fixed->parent. This saves you a kmalloc call and >> makes the error path simpler. It's the same way already done in the >> divider. I thought I had done this for v7... hmm looks like one got left out. I'll line up a patch to get it in sync with the others as part of my fixes. > I thought about that since I saw the same was done for gated and divider > (I think). Here is my guess at Mike's reasoning for this: > > Gated and divider clocks have to have a parent. There's nothing to gate > otherwise. But fixed rate clocks might not have a parent. It could be XO's > or PLLs running off of always on XOs not controlled by the SoC. So, it's > arguable to not have a parent. I don't have a strong opinion on this -- > since Mike took the time to write it, it left it to his subjective > preference. I appreciate the thoughtfulness. Re-using the same type of mechanism as the divider and gate clocks will still allow the fixed-rate clock to be parentless, and it makes for cleaner code, one less allocation and lines up with how the other single-parent basic clocks are done, so I'll take that method in instead of your patch. > I sent this patch first since it was around the place I was cleaning up. I > didn't want to actually just shuffle around a bug. As I mentioned, this > patch still leaves a bug open -- what if clk_register() fails. I plan to > fix that once my two patches are picked up (hopefully). Do you still find it useful to return -ENOMEM from the registration function instead of a NULL clock? I'm always worried that people don't check for error codes on pointers in their platform code and only check for NULL... Regards, Mike > Thanks, > Saravana -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
