fs: use small lock to protect filelist

Signed-off-by: hujun5 <[email protected]>

fs/inode/fs_files.c

@@ -72,7 +72,7 @@ static FAR struct file *files_fget_by_index(FAR struct filelist *list,
   FAR struct file *filep;
   irqstate_t flags;
 
-  flags = spin_lock_irqsave(NULL);
+  flags = spin_lock_irqsave(&list->fl_lock);
 
   filep = &list->fl_files[l1][l2];
 #ifdef CONFIG_FS_REFCOUNT
@@ -111,7 +111,7 @@ static FAR struct file *files_fget_by_index(FAR struct filelist *list,
     }
 #endif
 
-  spin_unlock_irqrestore(NULL, flags);
+  spin_unlock_irqrestore(&list->fl_lock, flags);
   return filep;
 }
 
@@ -165,7 +165,7 @@ static int files_extend(FAR struct filelist *list, size_t row)
     }
   while (++i < row);
 
-  flags = spin_lock_irqsave(NULL);
+  flags = spin_lock_irqsave(&list->fl_lock);
 
   /* To avoid race condition, if the file list is updated by other threads
    * and list rows is greater or equal than temp list,
@@ -174,7 +174,7 @@ static int files_extend(FAR struct filelist *list, size_t row)
 
   if (orig_rows != list->fl_rows && list->fl_rows >= row)
     {
-      spin_unlock_irqrestore(NULL, flags);
+      spin_unlock_irqrestore(&list->fl_lock, flags);
 
       for (j = orig_rows; j < i; j++)
         {
@@ -196,7 +196,7 @@ static int files_extend(FAR struct filelist *list, size_t row)
   list->fl_files = files;
   list->fl_rows = row;
 
-  spin_unlock_irqrestore(NULL, flags);
+  spin_unlock_irqrestore(&list->fl_lock, flags);
 
   if (tmp != NULL && tmp != &list->fl_prefile)
     {
@@ -371,6 +371,7 @@ void files_initlist(FAR struct filelist *list)
   list->fl_crefs = 1;
   list->fl_files = &list->fl_prefile;
   list->fl_prefile = list->fl_prefiles;
+  spin_lock_init(&list->fl_lock);
 }
 
 /****************************************************************************
@@ -589,21 +590,21 @@ int file_allocate_from_tcb(FAR struct tcb_s *tcb, FAR struct inode *inode,
 
   /* Find free file */
 
-  flags = spin_lock_irqsave(NULL);
+  flags = spin_lock_irqsave(&list->fl_lock);
 
   for (; ; i++, j = 0)
     {
       if (i >= list->fl_rows)
         {
-          spin_unlock_irqrestore(NULL, flags);
+          spin_unlock_irqrestore(&list->fl_lock, flags);
 
           ret = files_extend(list, i + 1);
           if (ret < 0)
             {
               return ret;
             }
 
-          flags = spin_lock_irqsave(NULL);
+          flags = spin_lock_irqsave(&list->fl_lock);
         }
 
       do
@@ -632,7 +633,7 @@ int file_allocate_from_tcb(FAR struct tcb_s *tcb, FAR struct inode *inode,
     }
 
 found:
-  spin_unlock_irqrestore(NULL, flags);
+  spin_unlock_irqrestore(&list->fl_lock, flags);
 
   if (addref)
     {

include/nuttx/fs/fs.h

@@ -49,6 +49,7 @@
 #include <nuttx/spawn.h>
 #include <nuttx/queue.h>
 #include <nuttx/irq.h>
+#include <nuttx/spinlock_type.h>
 
 /****************************************************************************
  * Pre-processor Definitions
@@ -491,6 +492,7 @@ struct file
 
 struct filelist
 {
+  spinlock_t        fl_lock;    /* Manage access to the file list */
   uint8_t           fl_rows;    /* The number of rows of fl_files array */
   uint8_t           fl_crefs;   /* The references to filelist */
   FAR struct file **fl_files;   /* The pointer of two layer file descriptors array */