what is the Math needed to read papers and dive deep into something comfortably.

I am currently doing my master’s , I did math (calculus & linear algebra) during my bachelor but unfortunately I didn’t give it that much attention and focus I just wanted to pass, now whenever I do some reading or want to dive deep into some concept I stumble into something that I I dont know and now I have to go look at it, My question is what is the complete and fully sufficient mathematical foundation needed to read research papers and do research very comfortably—without constantly running into gaps or missing concepts? , and can you point them as a list of books that u ‘ve read before or sth ?
Thank you.