Re: [PATCH 2/3] pstore/ram: Switch to persistent_ram routines

On Thu, May 17, 2012 at 12:15 AM, Anton Vorontsov anton.vorontsov@linaro.org wrote:

The patch switches pstore RAM backend to use persistent_ram routines, one step closer to the ECC support.

Signed-off-by: Anton Vorontsov anton.vorontsov@linaro.org Acked-by: Marco Stornelli marco.stornelli@gmail.com

---

fs/pstore/ram.c |  106 +++++++++++++++++++++++++++++++------------------------  1 file changed, 59 insertions(+), 47 deletions(-)

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index e443c9c..62b13ed 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -57,7 +57,7 @@ MODULE_PARM_DESC(dump_oops,                "set to 1 to dump oopses, 0 to only dump panics (default 1)");

struct ramoops_context {

• void *virt_addr;

• struct persistent_ram_zone **przs;

phys_addr_t phys_addr;        unsigned long size;        size_t record_size; @@ -85,39 +85,56 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,                                   struct pstore_info *psi)  {        ssize_t size;

• char *rambuf;

struct ramoops_context *cxt = psi->data;

• struct persistent_ram_zone *prz;

if (cxt->read_count >= cxt->max_count)                return -EINVAL;

*id = cxt->read_count++;

• prz = cxt->przs[*id];

/* Only supports dmesg output so far. */        *type = PSTORE_TYPE_DMESG;        /* TODO(kees): Bogus time for the moment. */        time->tv_sec = 0;        time->tv_nsec = 0;

• rambuf = cxt->virt_addr + (*id * cxt->record_size);
• size = strnlen(rambuf, cxt->record_size);

• size = persistent_ram_old_size(prz);

*buf = kmalloc(size, GFP_KERNEL);        if (*buf == NULL)                return -ENOMEM;

• memcpy(*buf, rambuf, size);

• memcpy(*buf, persistent_ram_old(prz), size);

return size;  }

+static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz) +{

• char *hdr;
• struct timeval timestamp;
• size_t len;
• do_gettimeofday(&timestamp);
• hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu\n",
• (long)timestamp.tv_sec, (long)timestamp.tv_usec);
• WARN_ON_ONCE(!hdr);
• len = hdr ? strlen(hdr) : 0;
• persistent_ram_write(prz, hdr, len);
• kfree(hdr);
• return len;

+}

static int ramoops_pstore_write(enum pstore_type_id type,                                enum kmsg_dump_reason reason,                                u64 *id,                                unsigned int part,                                size_t size, struct pstore_info *psi)  {

• char *buf;
• size_t res;
• struct timeval timestamp;

struct ramoops_context *cxt = psi->data;

• size_t available = cxt->record_size;

• struct persistent_ram_zone *prz = cxt->przs[cxt->count];
• size_t hlen;

/* Currently ramoops is designed to only store dmesg dumps. */        if (type != PSTORE_TYPE_DMESG) @@ -142,22 +159,10 @@ static int ramoops_pstore_write(enum pstore_type_id type,        if (part != 1)                return -ENOSPC;

• buf = cxt->virt_addr + (cxt->count * cxt->record_size);
• res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
• buf += res;
• available -= res;
• do_gettimeofday(&timestamp);
• res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
• buf += res;
• available -= res;
• if (size > available)
• size = available;
• memcpy(buf, cxt->pstore.buf, size);
• memset(buf + size, '\0', available - size);

• hlen = ramoops_write_kmsg_hdr(prz);
• if (size + hlen > prz->buffer_size)
• size = prz->buffer_size - hlen;
• persistent_ram_write(prz, cxt->pstore.buf, size);

This still needs to wipe out the remaining bytes in the buffer (the second memset above).

cxt->count = (cxt->count + 1) % cxt->max_count;

@@ -167,14 +172,12 @@ static int ramoops_pstore_write(enum pstore_type_id type,  static int ramoops_pstore_erase(enum pstore_type_id type, u64 id,                                struct pstore_info *psi)  {

• char *buf;

struct ramoops_context *cxt = psi->data;

if (id >= cxt->max_count)                return -EINVAL;

• buf = cxt->virt_addr + (id * cxt->record_size);
• memset(buf, '\0', cxt->record_size);

• persistent_ram_free_old(cxt->przs[id]);

Same here -- erasing the buffer means wiping it with NULL bytes.

Otherwise, it looks good to me.

-Kees