ublk: fix maple tree lockdep warning and unpin under spinlock

[blktests-ci]

Pull request for series with
subject: ublk: fix maple tree lockdep warning and unpin under spinlock
version: 1
url: https://patchwork.kernel.org/project/linux-block/list/?series=1084082

[blktests-ci]

Upstream branch: fb9d71c
series: https://patchwork.kernel.org/project/linux-block/list/?series=1084082
version: 1

Pull request is NOT updated. Failed to apply https://patchwork.kernel.org/project/linux-block/list/?series=1084082
error message:

Cmd('git') failed due to: exit code(128)
  cmdline: git am --3way
  stdout: 'Applying: ublk: fix maple tree lockdep warning and unpin under spinlock
Using index info to reconstruct a base tree...
M	drivers/block/ublk_drv.c
Falling back to patching base and 3-way merge...
Auto-merging drivers/block/ublk_drv.c
CONFLICT (content): Merge conflict in drivers/block/ublk_drv.c
Patch failed at 0001 ublk: fix maple tree lockdep warning and unpin under spinlock'
  stderr: 'error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config set advice.mergeConflict false"'

conflict:

diff --cc drivers/block/ublk_drv.c
index 8e5f3738c203,0a92569c0c7d..000000000000
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@@ -5441,68 -5424,36 +5441,93 @@@ static void ublk_unpin_range_pages(unsi
  }
  
  /*
++<<<<<<< HEAD
 + * Inner loop: erase up to UBLK_REMOVE_BATCH matching ranges under
 + * mas_lock, collecting them into an xarray. Then drop the lock and
 + * unpin pages + free ranges outside spinlock context.
 + *
 + * Returns true if the tree walk completed, false if more ranges remain.
 + * Xarray key is the base PFN, value encodes nr_pages via xa_mk_value().
 + */
 +#define UBLK_REMOVE_BATCH	64
 +
 +static bool __ublk_shmem_remove_ranges(struct ublk_device *ub,
 +					int buf_index, int *ret)
 +{
 +	MA_STATE(mas, &ub->buf_tree, 0, ULONG_MAX);
 +	struct ublk_buf_range *range;
 +	struct xarray to_unpin;
 +	unsigned long idx;
 +	unsigned int count = 0;
 +	bool done = false;
 +	void *entry;
 +
 +	xa_init(&to_unpin);
 +
 +	mas_lock(&mas);
 +	mas_for_each(&mas, range, ULONG_MAX) {
 +		unsigned long nr;
++=======
+  * Drop mas_lock during iteration to avoid unpinning pages under spinlock.
+  * Safe because callers hold ub->mutex (via ublk_lock_buf_tree), preventing
+  * concurrent tree modifications.
+  */
+ static int __ublk_ctrl_unreg_buf(struct ublk_device *ub, int buf_index)
+ {
+ 	MA_STATE(mas, &ub->buf_tree, 0, ULONG_MAX);
+ 	struct ublk_buf_range *range;
+ 	int ret = -ENOENT;
+ 
+ 	mas_lock(&mas);
+ 	mas_for_each(&mas, range, ULONG_MAX) {
+ 		unsigned long base, nr;
++>>>>>>> ublk: fix maple tree lockdep warning and unpin under spinlock
  
 -		if (range->buf_index != buf_index)
 +		if (buf_index >= 0 && range->buf_index != buf_index)
  			continue;
  
 -		ret = 0;
 -		base = mas.index;
 -		nr = mas.last - base + 1;
 +		*ret = 0;
 +		nr = mas.last - mas.index + 1;
 +		if (xa_err(xa_store(&to_unpin, mas.index,
 +				    xa_mk_value(nr), GFP_ATOMIC)))
 +			goto unlock;
  		mas_erase(&mas);
++<<<<<<< HEAD
 +		kfree(range);
 +		if (++count >= UBLK_REMOVE_BATCH)
 +			goto unlock;
++=======
+ 		mas_unlock(&mas);
+ 
+ 		ublk_unpin_range_pages(base, nr);
+ 		kfree(range);
+ 
+ 		mas_lock(&mas);
++>>>>>>> ublk: fix maple tree lockdep warning and unpin under spinlock
  	}
 +	done = true;
 +unlock:
  	mas_unlock(&mas);
  
 +	xa_for_each(&to_unpin, idx, entry)
 +		ublk_unpin_range_pages(idx, xa_to_value(entry));
 +	xa_destroy(&to_unpin);
 +
 +	return done;
 +}
 +
 +/*
 + * Remove ranges from the maple tree matching buf_index, unpin pages
 + * and free range structs. If buf_index < 0, remove all ranges.
 + * Processes ranges in batches to avoid holding the maple tree spinlock
 + * across potentially expensive page unpinning.
 + */
 +static int ublk_shmem_remove_ranges(struct ublk_device *ub, int buf_index)
 +{
 +	int ret = -ENOENT;
 +
 +	while (!__ublk_shmem_remove_ranges(ub, buf_index, &ret))
 +		cond_resched();
  	return ret;
  }
  
@@@ -5529,9 -5480,27 +5554,31 @@@ static int ublk_ctrl_unreg_buf(struct u
  	return ret;
  }
  
+ /*
+  * Drop mas_lock during iteration to avoid unpinning pages under spinlock.
+  * Safe because this is called from device release with exclusive access.
+  */
  static void ublk_buf_cleanup(struct ublk_device *ub)
  {
++<<<<<<< HEAD
 +	ublk_shmem_remove_ranges(ub, -1);
++=======
+ 	MA_STATE(mas, &ub->buf_tree, 0, ULONG_MAX);
+ 	struct ublk_buf_range *range;
+ 
+ 	mas_lock(&mas);
+ 	mas_for_each(&mas, range, ULONG_MAX) {
+ 		unsigned long base = mas.index;
+ 		unsigned long nr = mas.last - base + 1;
+ 
+ 		mas_erase(&mas);
+ 		mas_unlock(&mas);
+ 		ublk_unpin_range_pages(base, nr);
+ 		kfree(range);
+ 		mas_lock(&mas);
+ 	}
+ 	mas_unlock(&mas);
++>>>>>>> ublk: fix maple tree lockdep warning and unpin under spinlock
  	mtree_destroy(&ub->buf_tree);
  	ida_destroy(&ub->buf_ida);
  }