efi_pstore: Remove a logic erasing entries from a write callback to hold multiple logs

[Issue]

Currently, efi_pstore driver simply overwrites existing panic messages in NVRAM.
So, in the following scenario, we will lose 1st panic messages.

1. kernel panics.
2. efi_pstore is kicked and writes panic messages to NVRAM.
3. system reboots.
4. kernel panics again before a user checks the 1st panic messages in NVRAM.

[Solution]

A reasonable solution to fix the issue is just holding multiple logs without erasing
existing entries.
This patch removes a logic erasing existing entries in a write callback
because the logic is not needed in the write callback to support holding multiple logs.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 2 insertions, 37 deletions

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index bee14cc47c03..fbe9202c2678 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -701,18 +701,13 @@ static int efi_pstore_write(enum pstore_type_id type,
                 unsigned int part, size_t size, struct pstore_info *psi)
 {
         char name[DUMP_NAME_LEN];
-        char stub_name[DUMP_NAME_LEN];
         efi_char16_t efi_name[DUMP_NAME_LEN];
         efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
         struct efivars *efivars = psi->data;
-        struct efivar_entry *entry, *found = NULL;
         int i, ret = 0;
         u64 storage_space, remaining_space, max_variable_size;
         efi_status_t status = EFI_NOT_FOUND;
 
-        sprintf(stub_name, "dump-type%u-%u-", type, part);
-        sprintf(name, "%s%lu", stub_name, get_seconds());
-
         spin_lock(&efivars->lock);
 
         /*
@@ -730,35 +725,8 @@ static int efi_pstore_write(enum pstore_type_id type,
                 return -ENOSPC;
         }
 
-        for (i = 0; i < DUMP_NAME_LEN; i++)
-                efi_name[i] = stub_name[i];
-
-        /*
-         * Clean up any entries with the same name
-         */
-
-        list_for_each_entry(entry, &efivars->list, list) {
-                get_var_data_locked(efivars, &entry->var);
-
-                if (efi_guidcmp(entry->var.VendorGuid, vendor))
-                        continue;
-                if (utf16_strncmp(entry->var.VariableName, efi_name,
-                                  utf16_strlen(efi_name)))
-                        continue;
-                /* Needs to be a prefix */
-                if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
-                        continue;
-
-                /* found */
-                found = entry;
-                efivars->ops->set_variable(entry->var.VariableName,
-                                           &entry->var.VendorGuid,
-                                           PSTORE_EFI_ATTRIBUTES,
-                                           0, NULL);
-        }
-
-        if (found)
-                list_del(&found->list);
+        sprintf(name, "dump-type%u-%u-%lu", type, part,
+                get_seconds());
 
         for (i = 0; i < DUMP_NAME_LEN; i++)
                 efi_name[i] = name[i];
@@ -768,9 +736,6 @@ static int efi_pstore_write(enum pstore_type_id type,
 
         spin_unlock(&efivars->lock);
 
-        if (found)
-                efivar_unregister(found);
-
         if (size)
                 ret = efivar_create_sysfs_entry(efivars,
                                           utf16_strsize(efi_name,