ftrace: Store the order of pages allocated in ftrace_page

Instead of saving the size of the records field of the ftrace_page, store
the order it uses to allocate the pages, as that is what is needed to know
in order to free the pages. This simplifies the code.

Link: https://lore.kernel.org/lkml/CAHk-=whyMxheOqXAORt9a7JK9gc9eHTgCJ55Pgs4p=X3RrQubQ@mail.gmail.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ change log written by Steven Rostedt ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 22ecaaa13baa8e81e1c17621ff7c8e6ee50c9a97..f7bef5a9ada97f6f6f4aadb505bbc332960b8aa6 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1090,7 +1090,7 @@ struct ftrace_page {
        struct ftrace_page      *next;
        struct dyn_ftrace       *records;
        int                     index;
-       int                     size;
+       int                     order;
 };
 
 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
@@ -3181,7 +3181,7 @@ static int ftrace_allocate_records(struct ftrace_page *pg, int count)
        ftrace_number_of_groups++;
 
        cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
-       pg->size = cnt;
+       pg->order = order;
 
        if (cnt > count)
                cnt = count;
@@ -3194,7 +3194,6 @@ ftrace_allocate_pages(unsigned long num_to_init)
 {
        struct ftrace_page *start_pg;
        struct ftrace_page *pg;
-       int order;
        int cnt;
 
        if (!num_to_init)
@@ -3230,13 +3229,13 @@ ftrace_allocate_pages(unsigned long num_to_init)
  free_pages:
        pg = start_pg;
        while (pg) {
-               order = get_count_order(pg->size / ENTRIES_PER_PAGE);
-               if (order >= 0)
-                       free_pages((unsigned long)pg->records, order);
+               if (pg->records) {
+                       free_pages((unsigned long)pg->records, pg->order);
+                       ftrace_number_of_pages -= 1 << pg->order;
+               }
                start_pg = pg->next;
                kfree(pg);
                pg = start_pg;
-               ftrace_number_of_pages -= 1 << order;
                ftrace_number_of_groups--;
        }
        pr_info("ftrace: FAILED to allocate memory for functions\n");
@@ -6188,6 +6187,7 @@ static int ftrace_process_locs(struct module *mod,
        p = start;
        pg = start_pg;
        while (p < end) {
+               unsigned long end_offset;
                addr = ftrace_call_adjust(*p++);
                /*
                 * Some architecture linkers will pad between
@@ -6198,7 +6198,8 @@ static int ftrace_process_locs(struct module *mod,
                if (!addr)
                        continue;
 
-               if (pg->index == pg->size) {
+               end_offset = (pg->index+1) * sizeof(pg->records[0]);
+               if (end_offset > PAGE_SIZE << pg->order) {
                        /* We should have allocated enough */
                        if (WARN_ON(!pg->next))
                                break;
@@ -6367,7 +6368,6 @@ void ftrace_release_mod(struct module *mod)
        struct ftrace_page **last_pg;
        struct ftrace_page *tmp_page = NULL;
        struct ftrace_page *pg;
-       int order;
 
        mutex_lock(&ftrace_lock);
 
@@ -6418,12 +6418,12 @@ void ftrace_release_mod(struct module *mod)
                /* Needs to be called outside of ftrace_lock */
                clear_mod_from_hashes(pg);
 
-               order = get_count_order(pg->size / ENTRIES_PER_PAGE);
-               if (order >= 0)
-                       free_pages((unsigned long)pg->records, order);
+               if (pg->records) {
+                       free_pages((unsigned long)pg->records, pg->order);
+                       ftrace_number_of_pages -= 1 << pg->order;
+               }
                tmp_page = pg->next;
                kfree(pg);
-               ftrace_number_of_pages -= 1 << order;
                ftrace_number_of_groups--;
        }
 }
@@ -6741,7 +6741,6 @@ void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
        struct ftrace_mod_map *mod_map = NULL;
        struct ftrace_init_func *func, *func_next;
        struct list_head clear_hash;
-       int order;
 
        INIT_LIST_HEAD(&clear_hash);
 
@@ -6779,10 +6778,10 @@ void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
                ftrace_update_tot_cnt--;
                if (!pg->index) {
                        *last_pg = pg->next;
-                       order = get_count_order(pg->size / ENTRIES_PER_PAGE);
-                       if (order >= 0)
-                               free_pages((unsigned long)pg->records, order);
-                       ftrace_number_of_pages -= 1 << order;
+                       if (pg->records) {
+                               free_pages((unsigned long)pg->records, pg->order);
+                               ftrace_number_of_pages -= 1 << pg->order;
+                       }
                        ftrace_number_of_groups--;
                        kfree(pg);
                        pg = container_of(last_pg, struct ftrace_page, next);