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Message-ID: <20161014043143.GA8247@tuxbot>
Date: Thu, 13 Oct 2016 21:31:43 -0700
From: Bjorn Andersson <bjorn.andersson@...aro.org>
To: Matt Redfearn <matt.redfearn@...tec.com>
Cc: Ohad Ben-Cohen <ohad@...ery.com>, linux-remoteproc@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/4] remoteproc: Use fixed length field for firmware name
On Tue 11 Oct 06:39 PDT 2016, Matt Redfearn wrote:
> Storage of the firmware name was inconsistent, either storing a pointer
> to a name stored with unknown ownership, or a variable length tacked
> onto the end of the struct proc allocated in rproc_alloc.
>
Instead of using a statically sized array for "firmware", just keep it
a pointer to a local copy of the firmware name.
> In preparation for allowing the firmware of an already allocated struct
> rproc to be changed, the easiest way to allow reallocation of the name
> is to switch to a fixed length buffer held as part of the struct rproc.
> That way we can either copy the provided firmware name into it, or print
> into it based on a name template. A new function,
> rproc_set_firmware_name() is introduced for this purpose, and that logic
> removed from rproc_alloc().
>
> Signed-off-by: Matt Redfearn <matt.redfearn@...tec.com>
> ---
>
> drivers/remoteproc/remoteproc_core.c | 64 +++++++++++++++++++++++-------------
> include/linux/remoteproc.h | 4 ++-
> 2 files changed, 45 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index fe0539ed9cb5..48cd9d5afb69 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -1309,6 +1309,42 @@ static void rproc_type_release(struct device *dev)
> kfree(rproc);
> }
>
> +/**
> + * rproc_set_firmware_name() - helper to create a valid firmare name
> + * @rproc: remote processor
> + * @firmware: name of firmware file, can be NULL
> + *
> + * If the caller didn't pass in a firmware name then construct a default name,
> + * otherwise the provided name is copied into the firmware field of struct
> + * rproc. If the name is too long to fit, -EINVAL is returned.
> + *
> + * Returns 0 on success and an appropriate error code otherwise.
> + */
> +static int rproc_set_firmware_name(struct rproc *rproc, const char *firmware)
That would turn this function into something like:
char *p, *template = "rproc-%s-fw";
if (!firmware) {
name_len = strlen(name) + strlen(template) - 2 + 1;
p = kmalloc(name_len, GFP_KERNEL);
if (!p)
return -ENOMEM;
sprintf(p, template, firmware);
} else {
p = kstrdup(firmware, GFP_KERNEL);
if (!p)
return -ENOMEM;
}
kfree(rproc->firmware);
rproc->firmware = p;
Like your version this leaves the firmware name unchanged in the case of
an error.
> +{
> + char *cp, *template = "rproc-%s-fw";
> + int name_len;
> +
> + if (firmware) {
> + name_len = strlen(firmware);
> + cp = memchr(firmware, '\n', name_len);
Let's just require the caller to pass us a valid name.
> + if (cp)
> + name_len = cp - firmware;
> +
> + if (name_len > RPROC_MAX_FIRMWARE_NAME_LEN)
> + return -EINVAL;
> +
> + strncpy(rproc->firmware, firmware, name_len);
> + rproc->firmware[name_len] = '\0';
> + } else {
> + snprintf(rproc->firmware, RPROC_MAX_FIRMWARE_NAME_LEN,
> + template, rproc->name);
> + }
> +
> + dev_dbg(&rproc->dev, "Using firmware %s\n", rproc->firmware);
> + return 0;
> +}
PS. Don't forget to free the string in rproc_type_release()
Regards,
Bjorn
> +
> static struct device_type rproc_type = {
> .name = "remoteproc",
> .release = rproc_type_release,
> @@ -1342,35 +1378,14 @@ struct rproc *rproc_alloc(struct device *dev, const char *name,
> const char *firmware, int len)
> {
> struct rproc *rproc;
> - char *p, *template = "rproc-%s-fw";
> - int name_len = 0;
>
> if (!dev || !name || !ops)
> return NULL;
>
> - if (!firmware)
> - /*
> - * Make room for default firmware name (minus %s plus '\0').
> - * If the caller didn't pass in a firmware name then
> - * construct a default name. We're already glomming 'len'
> - * bytes onto the end of the struct rproc allocation, so do
> - * a few more for the default firmware name (but only if
> - * the caller doesn't pass one).
> - */
> - name_len = strlen(name) + strlen(template) - 2 + 1;
> -
> - rproc = kzalloc(sizeof(struct rproc) + len + name_len, GFP_KERNEL);
> + rproc = kzalloc(sizeof(struct rproc) + len, GFP_KERNEL);
> if (!rproc)
> return NULL;
>
> - if (!firmware) {
> - p = (char *)rproc + sizeof(struct rproc) + len;
> - snprintf(p, name_len, template, name);
> - } else {
> - p = (char *)firmware;
> - }
> -
> - rproc->firmware = p;
> rproc->name = name;
> rproc->ops = ops;
> rproc->priv = &rproc[1];
> @@ -1389,6 +1404,11 @@ struct rproc *rproc_alloc(struct device *dev, const char *name,
>
> dev_set_name(&rproc->dev, "remoteproc%d", rproc->index);
>
> + if (rproc_set_firmware_name(rproc, firmware)) {
> + put_device(&rproc->dev);
> + return NULL;
> + }
> +
> atomic_set(&rproc->power, 0);
>
> /* Set ELF as the default fw_ops handler */
> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> index 1c457a8dd5a6..7a6f9ad55011 100644
> --- a/include/linux/remoteproc.h
> +++ b/include/linux/remoteproc.h
> @@ -42,6 +42,8 @@
> #include <linux/idr.h>
> #include <linux/of.h>
>
> +#define RPROC_MAX_FIRMWARE_NAME_LEN 128
> +
> /**
> * struct resource_table - firmware resource table header
> * @ver: version number
> @@ -416,7 +418,7 @@ struct rproc {
> struct list_head node;
> struct iommu_domain *domain;
> const char *name;
> - const char *firmware;
> + char firmware[RPROC_MAX_FIRMWARE_NAME_LEN];
> void *priv;
> const struct rproc_ops *ops;
> struct device dev;
> --
> 2.7.4
>
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