tidy up swap_pager_putpages

[dougm]

Summary

(1) convert the panic() at the function's start into a KASSERT(), (2) convert sync into a bool-type variable async, (3) make the variable definitions style(9) compliant, and (4) move the calls to swp_pager_init_freerange() and swp_pager_freeswapspace() out from under the object lock.

[alc]

swap_pager.c

1366–1367

Isn't this assignment unnecessary?

1382

I think it's within the scope of this patch to fix the style issue here: Add spaces around the '+'.

1411–1412

Add spaces around the '+'.

[alc]

swap_pager.c

1355–1356

I think that this one line no longer applies.

1366

I would delete this blank line because the above block comment describes the below initialization to 'async'.

[dougm]

Apply reviewer suggestions. Make another style(9) fix.

[alc]

swap_pager.c

1335

Please fix the "whos".

1355–1356

Please capitalize and punctuate these sentences.

1387

Shouldn't this be a period instead of a comma?

[dougm]

Tidy up comments.

[alc]

I think that this is a good change and ready to commit. Give Kostik and Mark a chance to comment.