On Wed, Feb 10, 2021 at 02:28:54PM -0800, Drew Fustini wrote: > Add "pinmux-select" to debugfs which will activate a function and group > when "<function-name group-name>" are written to the file. The write > operation pinmux_select() handles this by checking that the names map to > valid selectors and then calling ops->set_mux(). > > The existing "pinmux-functions" debugfs file lists the pin functions > registered for the pin controller. For example: > > function: pinmux-uart0, groups = [ pinmux-uart0-pins ] > function: pinmux-mmc0, groups = [ pinmux-mmc0-pins ] > function: pinmux-mmc1, groups = [ pinmux-mmc1-pins ] > function: pinmux-i2c0, groups = [ pinmux-i2c0-pins ] > function: pinmux-i2c1, groups = [ pinmux-i2c1-pins ] > function: pinmux-spi1, groups = [ pinmux-spi1-pins ] > > To activate function pinmux-i2c1 and group pinmux-i2c1-pins: > > echo "pinmux-i2c1 pinmux-i2c1-pins" > pinmux-select > > Signed-off-by: Drew Fustini <[email protected]> > --- > drivers/pinctrl/pinmux.c | 107 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 107 insertions(+) > > diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c > index c651b2db0925..23fa32f0a067 100644 > --- a/drivers/pinctrl/pinmux.c > +++ b/drivers/pinctrl/pinmux.c > @@ -673,6 +673,111 @@ void pinmux_show_setting(struct seq_file *s, > DEFINE_SHOW_ATTRIBUTE(pinmux_functions); > DEFINE_SHOW_ATTRIBUTE(pinmux_pins); > > +#define PINMUX_MAX_NAME 64 > +static ssize_t pinmux_select(struct file *file, const char __user *user_buf, > + size_t len, loff_t *ppos) > +{ > + struct seq_file *sfile = file->private_data; > + struct pinctrl_dev *pctldev = sfile->private; > + const struct pinmux_ops *pmxops = pctldev->desc->pmxops; > + const char *const *groups; > + char *buf, *fname, *gname; > + unsigned int num_groups; > + int fsel, gsel, ret; > + > + if (len > (PINMUX_MAX_NAME * 2)) { > + dev_err(pctldev->dev, "write too big for buffer"); > + return -EINVAL; > + } > + > + buf = kzalloc(PINMUX_MAX_NAME * 2, GFP_KERNEL); > + if (!buf) > + return -ENOMEM; > + > + fname = kzalloc(PINMUX_MAX_NAME, GFP_KERNEL); > + if (!fname) { > + ret = -ENOMEM; > + goto free_buf; > + } > + > + gname = kzalloc(PINMUX_MAX_NAME, GFP_KERNEL); > + if (!buf) { > + ret = -ENOMEM; > + goto free_fname; > + } > + > + ret = strncpy_from_user(buf, user_buf, PINMUX_MAX_NAME * 2); > + if (ret < 0) { > + dev_err(pctldev->dev, "failed to copy buffer from userspace"); > + goto free_gname; > + } > + buf[len-1] = '\0'; > + > + ret = sscanf(buf, "%s %s", fname, gname); > + if (ret != 2) { > + dev_err(pctldev->dev, "expected format: <function-name> > <group-name>"); > + goto free_gname; > + } > + > + fsel = pinmux_func_name_to_selector(pctldev, fname); > + if (fsel < 0) { > + dev_err(pctldev->dev, "invalid function %s in map table\n", > fname); > + ret = -EINVAL; > + goto free_gname; > + } > + > + ret = pmxops->get_function_groups(pctldev, fsel, &groups, &num_groups); > + if (ret) { > + dev_err(pctldev->dev, "no groups for function %d (%s)", fsel, > fname); > + goto free_gname; > + > + } > + > + ret = match_string(groups, num_groups, gname); > + if (ret < 0) { > + dev_err(pctldev->dev, "invalid group %s", gname); > + goto free_gname; > + } > + > + ret = pinctrl_get_group_selector(pctldev, gname); > + if (ret < 0) { > + dev_err(pctldev->dev, "failed to get group selectorL %s", > gname); > + goto free_gname; > + } > + gsel = ret; > + > + ret = pmxops->set_mux(pctldev, fsel, gsel); > + if (ret) { > + dev_err(pctldev->dev, "set_mux() failed: %d", ret); > + goto free_gname; > + } > + > + return len; > + > +free_gname: > + devm_kfree(pctldev->dev, gname); > +free_fname: > + devm_kfree(pctldev->dev, fname); > +free_buf: > + devm_kfree(pctldev->dev, buf);
Ugh... I honestly thought Smatch was supposed to print a warning when you used devm_kfree() on kzalloc()ed memory, but I guess the warning is only the other way around. Smatch does complain about it as a leak because it was expecting a regular free. drivers/pinctrl/pinmux.c:330 pinmux_func_name_to_selector() warn: potential NULL parameter dereference 'fname' drivers/pinctrl/pinmux.c:764 pinmux_select() warn: possible memory leak of 'gname' drivers/pinctrl/pinmux.c:764 pinmux_select() warn: sscanf doesn't return error codes drivers/pinctrl/pinmux.c:764 pinmux_select() warn: returning success when sscanf failed And what about the success path? Shouldn't we free these on the success path as well? regards, dan carpenter
