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On 03/20/2012 05:13 PM, Turquette, Mike wrote:
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 = kmalloc(len, GFP_KERNEL); if (!parent_names) - goto out; + goto fail_str; strncpy(parent_names, 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.
No problem, go for it.
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...
The last discussion I remember, NULL was considered a valid clock. So, I think on error, we shouldn't ever return NULL when the return type is struct clk *.
Thanks, Saravana -- Sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum. -- 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