proc: commit to genradix

The new generic radix trees have a simpler API and implementation, and
no limitations on number of elements, so all flex_array users are being
converted

Link: http://lkml.kernel.org/r/20181217131929.11727-6-kent.overstreet@gmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Pravin B Shelar <pshelar@ovn.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 15 insertions, 28 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 1b548d060d28..f5ebdd87afb2 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -59,6 +59,7 @@
 #include <linux/capability.h>
 #include <linux/file.h>
 #include <linux/fdtable.h>
+#include <linux/generic-radix-tree.h>
 #include <linux/string.h>
 #include <linux/seq_file.h>
 #include <linux/namei.h>
@@ -92,7 +93,6 @@
 #include <linux/sched/coredump.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/stat.h>
-#include <linux/flex_array.h>
 #include <linux/posix-timers.h>
 #include <trace/events/oom.h>
 #include "internal.h"
@@ -2142,11 +2142,12 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
         struct task_struct *task;
         struct mm_struct *mm;
         unsigned long nr_files, pos, i;
-        struct flex_array *fa = NULL;
-        struct map_files_info info;
+        GENRADIX(struct map_files_info) fa;
         struct map_files_info *p;
         int ret;
 
+        genradix_init(&fa);
+
         ret = -ENOENT;
         task = get_proc_task(file_inode(file));
         if (!task)
@@ -2178,35 +2179,22 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
          */
 
         for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
-                if (vma->vm_file && ++pos > ctx->pos)
-                        nr_files++;
-        }
+                if (!vma->vm_file)
+                        continue;
+                if (++pos <= ctx->pos)
+                        continue;
 
-        if (nr_files) {
-                fa = flex_array_alloc(sizeof(info), nr_files,
-                                        GFP_KERNEL);
-                if (!fa || flex_array_prealloc(fa, 0, nr_files,
-                                                GFP_KERNEL)) {
+                p = genradix_ptr_alloc(&fa, nr_files++, GFP_KERNEL);
+                if (!p) {
                         ret = -ENOMEM;
-                        if (fa)
-                                flex_array_free(fa);
                         up_read(&mm->mmap_sem);
                         mmput(mm);
                         goto out_put_task;
                 }
-                for (i = 0, vma = mm->mmap, pos = 2; vma;
-                                vma = vma->vm_next) {
-                        if (!vma->vm_file)
-                                continue;
-                        if (++pos <= ctx->pos)
-                                continue;
 
-                        info.start = vma->vm_start;
-                        info.end = vma->vm_end;
-                        info.mode = vma->vm_file->f_mode;
-                        if (flex_array_put(fa, i++, &info, GFP_KERNEL))
-                                BUG();
-                }
+                p->start = vma->vm_start;
+                p->end = vma->vm_end;
+                p->mode = vma->vm_file->f_mode;
         }
         up_read(&mm->mmap_sem);
         mmput(mm);
@@ -2215,7 +2203,7 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
                 char buf[4 * sizeof(long) + 2]; /* max: %lx-%lx\0 */
                 unsigned int len;
 
-                p = flex_array_get(fa, i);
+                p = genradix_ptr(&fa, i);
                 len = snprintf(buf, sizeof(buf), "%lx-%lx", p->start, p->end);
                 if (!proc_fill_cache(file, ctx,
                                       buf, len,
@@ -2225,12 +2213,11 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
                         break;
                 ctx->pos++;
         }
-        if (fa)
-                flex_array_free(fa);
 
 out_put_task:
         put_task_struct(task);
 out:
+        genradix_free(&fa);
         return ret;
 }